16mm Miniature dc Motor, Model B. Revised brushgear for improved commutation and reliability Replacements for Miniature dc Servo Motors (stock nos. ; 440-111 440-111 ; ; 440-127 440-127 ) Can be used with 16mm and planetary gearheads Speed Constant: 1390rpm/V (stock no. ; 420-5164 420-5164 ); 586rpm/V (stock no. ; 420-5170 420-5170 )