This Sea & Sea o-ring set is for the YS-01, YS-02, YS-90, YS-110, YS-110a YS-27, and YS-30 strobes. The o-ring resembling a thick rubber band is designed to establish a watertight seal when going underwater.

Made of elastomeric material and manufactured to the precision tolerances required to hold a pressure seal on your housing, it provides the means by which a watertight seal is formed.