Mixers come in manual (non-powered) designs, battery-powered portable mixers, and electric countertop units. Battery models commonly use AA batteries, while countertop units plug into mains power.
Capacity depends on bottle size: for example, a mixing pitcher may prepare up to four 8 oz (about 250 mL) bottles at once. Compartment-style dispensers are sized by pre-measured scoops and commonly hold enough powder for about three 9 oz (270 mL) bottles in some designs.
Look for adjustable time rings or markings to track when formula was mixed, locking or snap-on lids, no-drip or pour-control spouts, and airtight seals or latches to reduce spills and leaks.
Compartment dispensers vary: some have four airtight compartments that can hold up to about 12 scoops each (suitable for bottles up to about 12 oz), while three-compartment designs are commonly sized to supply roughly three 9 oz (270 mL) bottles.
Many warm-water dispensers offer three preset temperatures commonly described as room temperature, body temperature, and slightly warmer than body temperature to match typical bottle-prep needs.