iOptron offers this 7" long Dovetail Plate for mounting small to medium optical tube assemblies (OTAs), DSLRs, or other accessories on mounts or secondary systems with ease. The plate is made of a lightweight and durable aluminum alloy with a scratch-resistant black anodized finish. It has pre-drilled holes set at common intervals in standard sizes with separations of 1.5" and 3", with a long 1/4" slot that is ideal for mounting and properly balancing a DSLR and long lens for wide-field astrophotography.