# Best rock tumbler replacement barrels and lids by size Source: https://tumblegrit.com/best/best-rock-tumbler-replacement-barrel Publisher: Tumble Grit. Picks are chosen from what each Amazon listing states, not from hands-on tests. Method: https://tumblegrit.com/how-we-pick A leaking or worn barrel does not mean a new tumbler, and a second barrel kept only for polish (step 4) stops coarse grit from carrying over and scratching the batch. The catch is fit. Barrels are not interchangeable: each one is made for the roller spacing of specific machines, so the first thing to check is which tumbler models the listing names. Match the part to the model name on your own machine before anything else, and if your model is not named, do not assume it fits. After fit, the listings differ in capacity (2.5 to 4 lb here), material (every barrel below is rubber, which runs quieter than hard plastic) and the lid: some state a leak-proof lid, one has a steel outer lid over a rubber inner lid, and one does not mention the lid at all. If the barrel is sound and only the lid leaks or the knob is lost, a lid kit may be all you need, so two are included. This guide compares what each listing states. Nothing here was tested. ## Picks ### 1. KomeStone Replacement Rubber Barrel K2 Elite Rock Tumbler - 3 lbs Capacity, Leak-Proof, Durable, Upgraded Twist Knob - Easy to Close and Open Fits: KomeStone K2 Elite; Capacity: 3 lb (4.2 lb total load); Material: Tire-grade rubber; Lid: Twist-knob closure Drop-in replacement barrel made for the KomeStone K2 Elite. Rated 3 lb, with the listing giving 4.2 lb as the total of rocks, water, grit and media, and a redesigned twist knob. What the listing offers: - Engineered specifically for the K2 Elite, so there is no guessing about roller spacing on that model. - States both figures: 3 lb capacity and up to 4.2 lb total including rocks, water, grit and media. - New 8-thread twist knob replaces the older round knob, plus thick tire-grade rubber and a 1-year warranty. Limits to know: - Only the K2 Elite is named; the listing gives no fit for the K1, K1 Pro or tumblers from other brands. - The two capacity figures (3 lb and 4.2 lb total) are not explained further, so load by your tumbler manual. ### 2. AtoRock Rock Tumbler Replacement Barrel, Extral Large Capacity 4Lbs, Rubber Material, with Durable Leak-Proof Lid, Compatiable A1&A1Pro Rock Tumbler Fits: AtoRock A1, A1 Pro; Capacity: 4 lb; Material: Rubber; Lid: Steel outer + rubber inner The largest barrel in this guide: a 4 lb rubber drum for the AtoRock A1 and A1 Pro with a two-part lid, stainless steel outside and rubber inside. What the listing offers: - Designed to fit the A1 and A1 Pro rock tumblers, per the title and the first bullet. - Dual lid: a stainless steel outer lid combined with a rubber inner lid for double protection against spills. - 4 lb capacity and a 1-year replacement warranty with a support address in the listing. Limits to know: - No dimensions are given, so you cannot check it against a barrel from another brand. - The listing does not say whether 4 lb means rock alone or the full load with water and grit. ### 3. Replacement Rock Tumbler Barrel for National Geographic Tumblers Fits: Nat Geo, Dr. Cool Pro/Hobby; Capacity: not stated; Material: Rubber; Lid: Leak-proof lid Rubber barrel sold by Discover with Dr. Cool for the National Geographic Professional and Hobby Series tumblers and the matching Dr. Cool machines. The obvious choice for a polish-only barrel on those kits. What the listing offers: - Listing names the National Geographic Professional and Hobby Series tumblers and the Dr. Cool Professional and Hobby Series tumblers. - Described as durable rubber with a leak-proof lid and designed to be low-noise. - The listing itself suggests keeping one barrel only for the final polish step so coarser grit cannot scratch the stones. Limits to know: - No capacity in pounds is given in the listing, so confirm it matches the barrel your tumbler shipped with. - Does not say whether it fits National Geographic models outside the Professional and Hobby Series. ### 4. KomeStone Rock Tumbler Replacement Rubber Barrel for K1 & K1 Pro - 2.5 lb Heavy-Duty Drum, Leak-Proof & Durable Upgrade Fits: KomeStone K1, K1 Pro; Capacity: 2.5 lb; Material: Tire-grade rubber; Lid: not stated 2.5 lb rubber drum made only for the KomeStone K1 and K1 Pro. The listing stresses thick tire-grade rubber and an upgraded molded seal, and is blunt that it fits nothing else. What the listing offers: - Fit is spelled out: KomeStone K1 and K1 Pro only, not compatible with other models or brands. - Thick tire-grade rubber that the listing says absorbs vibration and reduces operating noise. - Upgraded molded rubber construction for a tighter seal, backed by a 1-year warranty. Limits to know: - The listing does not say whether the lid and knob come with the barrel; check the photos before ordering. - At 2.5 lb it is among the smaller barrels here, and the listing does not say whether that figure counts water and grit. ### 5. KoolStone Rock Tumbler Replacement Barrel - 3 Lbs (5 x 5 inch), Rubber Material with Durable Leak-Proof Lid, Compatible with C1ProMax Fits: KoolStone C1ProMax; Capacity: 3 lb (5 x 5 in); Material: Rubber; Lid: Leak-proof lid 3 lb rubber barrel, 5 x 5 inches, that the listing says fits the KoolStone C1ProMax. It warns that different shaft spacing on other machines may make it incompatible. What the listing offers: - States the fit (C1ProMax) and the size (5 x 5 inch), which lets you compare it against your old barrel. - Thick rubber construction that the listing says absorbs stone collision noise. - Comes with a sealed leak-proof lid according to the title and bullets. Limits to know: - The bullet is headed 'wide compatibility' but only the C1ProMax is named; treat it as a one-model part. - No warranty term is stated, and the lid design is not described beyond 'leak-proof'. ### 6. Stainless Steel Lid Kit Replacement for Rock Tumbler - Fits KomeStone K1, K1 Pro, K2 & K4 Rubber Barrels Only, Durable Sealing Lid Set Fits: KomeStone K1, K1 Pro, K2, K4; Capacity: Lid kit, no barrel; Material: Stainless steel; Lid: Inner lid, housing, knob Lid-only kit for KomeStone K1, K1 Pro, K2 and K4 rubber barrels: stainless steel inner lid, outer lid housing and a black tightening knob. For a leaking or incomplete lid when the barrel itself is fine. What the listing offers: - Names the barrels it fits: KomeStone K1, K1 Pro, K2 and K4 rubber barrels. - Includes the stainless steel inner lid, the outer lid housing and the black tightening knob. - Stainless steel lid described as corrosion-resistant, with a triple-layer sealing design. Limits to know: - Lid parts only: no barrel is included, and the title says it fits these KomeStone rubber barrels only. - The fit list names K1, K1 Pro, K2 and K4; the K2 Elite is not listed by that name, so confirm before ordering. ### 7. KoolStone Extra Large Rock Tumbler Barrel - 2.5 Lbs (5 x 4 inch), Rubber Material with Durable Leak-Proof Lid, Compatible with C1 & C1 Pro Fits: KoolStone C1, C1 Pro; Capacity: 2.5 lb (5 x 4 in); Material: Rubber; Lid: Leak-proof lid 2.5 lb rubber barrel, 5 x 4 inches, made for the KoolStone C1 and C1 Pro. The listing opens with a notice that axle spacing differs on other models. What the listing offers: - Specifically designed for the C1 and C1 Pro, with a clear notice to confirm your model before ordering. - Title gives the size as 5 x 4 inch and names a durable leak-proof lid. - Made from what the listing calls upgraded rubber that reduces noise during a run. Limits to know: - Not stated to fit the C1ProMax, which has its own 3 lb barrel listing. - Only four bullets, with no detail on the lid parts and no warranty term. ### 8. KoolStone Rock Tumbler Barrel 's Top Lid Accessories, Only Compatiable C1, C1 Pro, C1 Pro Max, C1 Pro Ultra Rock Tumbler, Double Leak-Proof Design - Diameter 5 inches Fits: C1, Pro, Pro Max, Pro Ultra; Capacity: Lid only, 5 in diameter; Material: Rubber inner, metal outer; Lid: Inner lid, outer lid, knob Replacement top lid, 5 inches across, for KoolStone C1, C1 Pro, C1 Pro Max and C1 Pro Ultra tumblers. A rubber inner lid sits under a metal outer lid with a large hand knob. What the listing offers: - Title lists four compatible tumblers: C1, C1 Pro, C1 Pro Max and C1 Pro Ultra. - Double leak-proof design with a rubber inner lid and a metal outer lid. - Enlarged hand-tightening knob that the listing says is easier to grip and turn. Limits to know: - Lid only, and the title says it is compatible with those four KoolStone models and no others. - Materials are described loosely: the metal is not named and no warranty term is given. As an Amazon Associate I earn from qualifying purchases.