This adapter aligns the GoPro lens center with the light axis of the SYSTEM series single light when using the GoPro Adapter or GoPro Adapter 2 with the SYSTEM series single light. Product Name: GoPro Offset Adapter ST Color: Black Included: None (no packaging) I purchased this on Mercari, thinking it was a necessary part, but it turned out to be unnecessary, so I am selling it. It has never been submerged in seawater, but it has been handled by someone else once. The original storage bag was dirty, so I will ship it in a different bag.