Thanks for contacting Tundra Restaurant Supply with your question.
No, this Cadco BRS117 Warmer Thermostat will not fit your KR S2 unit. You'll want Cadco part #KRP-18. We don't currently stock this part, but we special order for customers on a daily basis. Please give a member of our team a call at 1-888-388-6372 and we'll get this part ordered for you.