This iOptron plate adapter was originally intended for the SkyTracker Camera Mount. However we have found this dovetail plate works perfectly with all iOptron mounts as well as a wide variety of other mounts. This Vixen-style dovetail plate is 6.5" long, and is drilled with threaded holes for the iOptron ball head or the counterweight. With the addition of this adapter, you can ride two DSLR cameras on the SkyTracker Mount at once, or counterweight a heavier system if you choose.