Audiopak was a broadcast cartridge format, very similar to and a competitor to Fidelipac, and was introduced by Capitol Records in 1972. The Audiopak brand was also previously used for Capitol 8-Track cartridges.
There were two versions, the original A-2 with black casings, and later AA-3 mostly with blue casings.
Playing times for the A-2 version were between 20 seconds and 10.5 minutes.
The A-2 has no hub brake, and the tape itself is braked, with the aim of providing more reliable cueing. The AA-3 did away with the brake, and replaced it with a brake pad on the left side, to reduce the number of parts.
Like other broadcast cartridge formats, Audiopak was used by radio stations until the 1990s, when such formats as MiniDisc and computerised broadcast automation made it obsolete.