The SCMS-187 is a medium-sized premium suction cup with a .16" stem hole, combined with a 1/8-inch diameter x 1/2-inch long pan head screw. The screw fits the suction cup's stem hole and is used to affix signs to the suction cup.
The SCS-187 is a medium-sized premium suction cup which has a 1/8" stem hole (larger than our standard suction cups). This larger hole accommodates a 1/4" long binding screw. The screw passes through drilled or punched holes in signs. It then grips the hole in the suction cup's stem holding signage in place.