1.0 mm thick, 0.8 cm wide for xi to XL conversion spacer (BIO-RAD catalog #165-1836) for the BIO-RAD PROTEAN II, 1 set (package of 2 spacers). These spacers increase the gel width to 18.5cm, which is required to accept the 17cm ReadyStrip IPG strip for the second dimension of a 2D gel run. For use with IPG comb: Cat# CBXLSR-100.