Not OP but loved the idea and here is what I found.

Blue Panda Silicone Slap Bracelets - 24-Pack Kids Soft Bracelets Party Favors for Girls and Boys Birthday, Classroom Rewards, Carnival Prizes, 4 of Each 6 Colors, 8.5 x 1 inches https://www.amazon.com/dp/B07D3L287V/ref=cm_sw_r_cp_apa_i_Zfz1DbJ0N9DG9