CoverUp Add-On and replacement collar unit with Black belt for the H2O 1810 and 1820 PLUS CoverUp. Collar Unit - 2 5/8 in. x 2 in. x 1 1/2 in., 8.2 oz. (with belt) This collar is compatible with DT Systems H20 1810 PLUS, 1820 PLUS, or 1830 PLUS . you can also replace lost or damaged H2O 1800 PLUS Series collars or "Non-PLUS" H2O 1800 Series collars. These are the original replacement collar for the Cover Up 1810 and 1820 camo systems. This collar is also compatible with DT Systems Micro-iDT PLUS training collars.