Suunto, Service Kit for Core/Essential: O-ring and instrucctions, For Suunto Core, Essential, Lumi, T4, T3 and T1, SS023326000 Sports - Price comparison
Replacement Battery Kit for Suunto Observer, X6, X6HR and G6 | DiveSummit.com
Suunto Core Series All Steel Battery Cover Waterproof Ring -- Battery Kit Includes A Battery Lid And O-ring - Digital Wristwatches - AliExpress
Steel Battery Back Cover Case/Sealing Ring fit for SUUNTO CORE Watch Accessories | eBay