This pack contains a large amount of centering rings of appropriate measures for Estes BT-5 (18 mm), BT-20 (18 mm), BT-50 (24 mm) and BT-55 (34 mm) body tubes.

The centering rings are the same as included in the various Estes kits and are used to mount smaller diameter tubes inside tubes of larger diameter. The most common use is to make engine mounts, but they are also much used when it is necessary to fit together tubes of different diameter.

The rings are made of thick cardboard, which can be glued with aliphatic glue like Elmer Wood Glue.

The package contains 26 pieces as follows:

• 8 pcs. BT-5 to BT-20.
• 4 pcs. BT-5 to BT-50.
• 8 pcs. BT-20 to BT-50.
• 2 pcs. BT-20 to BT-50 - Length 25 mm
• 4 pcs. BT-50 to BT-55.