Not your ordinary over-the-counter O-ring, heavy duty 1/8" thick ideal for running 3s setups! Great replacements for our 24-30g out-runner prop savers o-rings. These o-rings were made to handle all the stresses you can throw it them.
Please note these are very tuff and do not wear out do to the nature of the material. Its best to use WD-40 or other lubricate to aid in getting these o-rings around the prop saver screws since they are over sized.
( 5 O-rings included ).