Sight glass and O' ring for front master cylinder to suit the models listed below.

K1 09/1988 - 08/1993 K100RS 16v 09/1989 - 08/1992

K1100LT 09/1991 - 08/1999K1100RS 09/1992 - 08/1996

Also used on R1100GS 09/1993 - 08/1999, R1100R 09/1994 - 08/2001, R1100RS 09/1993 - 08/2000, R1100RT 09/1994 - 08/2001, R850GS 09/1998 - 08/2000, R850R 08/1994 - 08/2002, R850RT 09/1996 - 08/2001

These are actually made from plastic, not glass

Lube the O' ring with a little brake fluid to aid in fitting. No warranty on it if you stuff it up. You could purchase a new O' ring as a spare just in case you do.