Bag was the first single to be released from the Afterburner album and
reached No.27 in the UK and No.8 on the Billboard Hot 100 in the U.S. The song also topped the U.S. Mainstream Rock charts, making this ZZ Top's most successful single.
The B-side features a 2:48 track entitled Party On The Patio.
The only other Top 40 hit single from the album (in the UK) was Rough Boy which charted higher than Sleeping Bag peaking at #23, although Stages came close to the Top 40 just stalling No.43.
This was the American rock band's last Top 40 hit of the 80s in the British Singles Chart. However, the lead single from the next album, Recycler, entitled Doubleback reached #29 during 1990.
The band's last Top 40 hit in the UK was Pincushion in 1994 which was their second-highest charting single, reaching #15. It featured on the Antenna.