A good value, and a must if you're going to build your own payloaders!
Clear plastic payload tubes come 3 each in 3 different sizes:
The BT-20 tubes are 2 3/4" (7cm) in length.
The BT-50 tubes are 4" (10.2cm) in length.
The BT-60 tubes are 5" (12.7cm) in length.
9 pcs total.