Keeler Charger or Docking System for Slimline Wireless Binocular Indirect Ophthalmoscopes. This charging station accomodates new Slimline lithium-ion battery modules, which are half the size of standard batteries and snap into place, just next to headband adjustment knob in back of the BIO. Current Keeler factory part number 1945-P-5012. Charger is desktop or wall mountable. Extra battery is in the top compartment with easy release button. The new All Pupil II and Vantage Plus Indirects feature this Slimline Wireless system.