www.safetyandhealthmagazine.com/articles/button-and-rotary-switch-covers-2

Button and rotary switch covers

December 1, 2011
The S2152 Push Button and Rotary Switch Covers for lockout/tagout protection fit both 30.5-mm and 22.5-mm diameter switches and accommodate buttons up to 2 inches in diameter. The horseshoe-shaped clear base and cover allows visibility and use with raised nameplates and off-center installation for the use of rotary switch knobs. 

Master Lock Co.