On-Off switch used in the newer White-Rodgers electronic air cleaners, including the SST, UST, SRP, SS, TTW series.
SPST (single pole, single throw). Has two 1/4" spade terminals. Fits in a rectangular hole slightly larger than 1-1/8 x 1/2 inch. Rating 16 amp at 125 vac or 10 amp at 250 vac.