The DYNA MAXX Bar Collar with chain hoop was an innovation in powerlifting for adding variable weights to a barbell. Sold in pairs, minimum order: one (1) pair.
First and foremost, the bar collar is one of the best bar-fasteners for keeping weights rock-steady, especially at higher weights. Because of its shape and the screw-tightened design, weights remain in place and stable compared to other fasteners, such as spring clips. Just for keeping the weights where you expect them to be, this bar collar is exceptional.
The exciting innovation that the chain hoop adds is the ability to easily clip variable-weight accessories, such as chains to the bar. In doing so, the lifter gets an increasingly heavy repetition as the bar rises. This is incredibly effective in the powerlifting staple exercises: squat, deadlift, and bench press.
There are several version of this collar on the market, but the DYNA MAXX design is the original and still the best after years in the field. Each collar weighs approximately 2.5 lbs (1.13), for a total of 5 lbs (2.27 kg) added to the bar.