Solid State Rectifier, positive and negative applications. Replaces the lucas finned rectifier fitted to many British bikes from the early 1950's to the late 1970's and will suit all 6V/12V models fitted with an alternator except the later electric start Triumphs and Nortons. 

Earth (Pos/Neg): Both
Voltage: Both 6v and 12v
Single Phase: Yes
 
OEM:  99-9882