Types

Flash-memory players

These are the smallest and lightest types of MP3 players, often no bigger than a pack of gum, and they typically weigh no more than 3 ounces. They're solid-state, meaning they have no moving parts and tend to have longer audio playback time than players that use hard-disk storage. Storage capacities range from 512MB to 64GB, or about 120 to 16,000 songs. (All song capacities listed here are based on a standard CD-quality setting of 128 kilobytes per second, which requires about 1GB per 250 songs. You can fit more music into memory if you compress songs into smaller files, but that may result in lower audio quality.) Some flash-memory players also have memory-card expansion slots to add more capacity. These typically use Secure Digital cards, though some Sony players use MemoryStick media. Memory-card capacities range from about 32MB to 32GB. Memory costs have gradually dropped. Price: $40 to $500 for the player; $12 to $15 for a 2GB memory card.

Hard-disk players

This type of MP3 player ranges from palm-size microdrive players that weigh about a quarter-pound and have a storage capacity of 4GB (about 1,000 songs) to brick-like bruisers that weigh more than a pound and whose 160GB hard drives can hold up to 40,000 songs.

Cell phones

An increasing number of phones have built-in MP3 players, some with controls and features that rival stand-alone players. Sprint, Verizon, and other cell-phone providers let subscribers download music over their networks. But songs are pricey: 99 cents to $2.50 per song. Song capacity is often determined by the size of the external memory card, as well as the phone manufacturer, carrier, or music provider.

Satellite radio

Some pocket-sized XM and Sirius receivers have built-in memory for recording up to 50 hours of satellite programming, and might also let you add your own MP3 songs to the mix. Not all models let you listen to live programming on the go; some must be docked at home.

See also:

Bluetooth headsets

Cell phones

Special Section:
Guide to mobile electronics

Special Section:
Apple's iPhone