2b single mounting facility thread class 1.570" overall length 1.570" overall width 40 single mounting facility thread quantity per inch a. no. 1 coil controls no. 2 coil capacitor delay. thus delaying contact transfer by no. 3 coil on drop-out. unc single mounting facility thread series
2a single mounting facility thread class 0.734" overall length 0.938" overall width 48 single mounting facility thread quantity per inch unc single mounting facility thread series
2b single mounting facility thread class 2.000" overall length 1.875" overall width 32 single mounting facility thread quantity per inch unc single mounting facility thread series