Wanted: Tank track flaps

My students are getting a VEX robot ready for competition and we have extended our tank tracks but did not receive enough of the 1 1/4" X 1 1/2" flaps that slide into the track tread. Does anyone have any extras they want to sell or any ideas where to get some. We are hoping to find about 15-20 of them. Please email: smcconkey@mahnomen.k12.mn.us
Thank you.