20 amp slow blow fuse 600v - class G type
With up to a 600V rating, they can be used in 120/208V, 120/240V, and 277/480V circuits.

Features :
Meets basic protection requirements of NEC®, Canadian Electrical Code (CEC), UL and CSA.
Most economical overcurrent protection solution compared to circuit breakers.
Compact branch-circuit units with high interrupting rating and current-limitation.