A: Socket Comparasion

　　As follow they are usually used in T25 Auto Turning light and Auto Brake light .Please pay more attention different socket have different namesin different country , Take this pictures as an example:

　　BA15S ( BS ) : also named “ 1156 “ “ P21W” (with one contact in the socket, two points in the side of socket with 180 degree )

　　BAU15S ( BU ): also named “ PY21W” ( with one contact in the socket, two points in the side of socket with 150 degree )

　　BA15D ( BD ): with two contacts in the socket, two points in the side of socket with 180 degree )

　　BAY15D ( BY ): also named “1157 ““ P21/5W” with two contacts in the socket, two points in the side of socket with 180 degree ,meanwhile the two points they are not in one line, one of the point higher than another )

　　Remark:: http://www.dingjuled.com/Helps/AutomotiveBulbSocket.html   (this is the link of different socket name)

　　B: Different of BA15D ( BD ) Socket

　　       A:                                                                 B:           
 

　　C: Difference of the contact

　　In this picutures, we can see , there are two type contacts in the socket (Crescent and Round Contacts )

　　The left one is Crescent Contacts , the right one is Round contacts which is suitable for Korean market .