O Rings
Two sizes, both hard-to-find 90 durometer to limit twisting
!

one dozen, small O rings
!
For F1D, EZB, Intermediate Stick, etc.

one hundred small O rings
!
For F1D, EZB, Intermediate Stick, etc.

one dozen large O rings
!
For Pennyplane, Science Olympiad

one hundred large O rings
!
For Pennyplane, Science Olympiad