Suunto, Service Kit for Core/Essential: O-ring and instrucctions, For Suunto Core, Essential, Lumi, T4, T3 and T1, SS023326000 Sports - Price comparison
Suunto Core All Black - My buddy got it for me a few Years ago. Super dependable. Needs a battery annually. It's seen U.S., Germany, Romania, Iceland, Mexico, Kuwait, and Syria. :
Suunto SS014279010 - Core All Black Watch • Watchard.com