Wall mount dispenser is required for 4-liter Pumicized Citrus Lotion Hand Cleaner Tub. The back plate is mounted to wall. Dispenser/reservoir unit locks into bottom portion of mounting plate. Refill is placed foil seal down and inserted into mount. Product flows into reservoir emptying completely during use with no waste. Empty tank can be changed while product reservoir still contains product. You get 1,444 dispensings from each refill.