Cold time varies by product: some breastmilk storage kits report keeping milk cold for 16+ hours, while reviews of insulated hard-sided coolers report ice retention and cold storage for up to about three days, depending on ice amount and ambient conditions.
Small electric mini fridges typically use an adjustable thermostat or a multi-position temperature control knob. For example, one mini fridge lists a 7-position knob with an adjustable range of about 40–61°F.
Small electric mini fridges in the set are described as low-power and quiet: one unit is listed at about 60 watts, and one model is noted to operate at around 40 dB or less. Actual power draw and noise will vary by model and operating conditions.