Razer's BlackWidow Lite TKL mechanical keyboard includes o-rings at $72 (Reg. $90)
Mechanical Keyboard O Ring Installation Razer Blackwidow Chroma V2 Yellow Switch - YouTube
Razer BlackWidow Elite Wired Green Switch w/ O-ring Mod (RZ03-02620200-R3U1) 897126000119 | eBay
Custom White Razer BlackWidow 2012 Edition with O-rings and vortex doubleshot pbt keycaps! :) : r/MechanicalKeyboards
Amazon.com: Razer BlackWidow TE Chroma v2 TKL Tenkeyless Mechanical Gaming Keyboard: Yellow Key Switches, Linear & Silent, Chroma RGB Lighting, Magnetic Wrist Rest, Programmable Macros, Classic Black : Video Games
Razer BlackWidow Lite Wired TKL Mechanical Gaming Keyboard - Black - iCuracao.com
Red, Blue & Black O-Rings arrive at Keyboard Co – The Keyboard Company
Razer BlackWidow Chroma V1 With O-Rings | Razer Green | eBay