Many warmers are marketed as compatible with most bottle types and with milk storage bags, pouches, jars and other containers thanks to universal warming chambers or removable baskets. Compatibility does vary by model, so check the product listing (supported bottle types or chamber dimensions) to confirm a specific bottle or container will fit.
Many models include automatic shut-off that stops heating at the end of a cycle. Some also offer built-in timers or timing controls that end the cycle to reduce overheating risk.
Times vary by design and mode: some quick or steam settings warm a bottle in about 2 minutes, many electric warmers heat a small bottle in around 3 minutes, and instant water dispensers provide warm water on demand.
Controls vary from a few fixed temperature choices to multiple preprogrammed settings. Some units offer many presets (for example, up to nine), others provide three to four temperature options, and a few use sensors or app control to adjust warming time based on bottle volume and starting temperature.