Push to reset. Calibrated and tested. Single pole circuit breakers. A proven "Snap-Acting" bi-metallic thermal sensing mechanism used to interrupt current flow. Manual push to reset reinstates current flow 

Max panel thickness : 1/4", 3/8" hole. 
1/2" W x 1-1/4" H x 1-1/2" D.

Note: Clear Breaker Boot (3019) does not fit the 90° blade breaker