The Jobu Design Hockey Puck, 75 g (3 oz) Counterweight is a small, stackable counterweight suitable for quick fixes of tricky-to-balance setups of lenses and cameras. It features primarily to be used when an ultralight camera is paired with a heavy lens. For example, the Canon 7D is very popular for nature photographers due to it's 1.6 x conversion factor, but it does not balance well with the 500F4 mk I lens (when used without a battery grip and a replacement foot). The typical solution is to add a flash, tele-extenders or use a much longer lens-plate.