Alliance 42339 Antimicrobial Non-Latex Rubber Bands, Sz. 33, 3-1/2 x 1/8.25lb Box Sold as 1/BX. Made with non-latex synthetic rubber. The antimicrobial product additive inhibits the growth of fungi, molds and bacteria that can cause early product deterioration. The antimicrobial treatment permeates the rubber band, protecting it on all surfaces for its lifetime. Can be sterilized using autoclave and irradiation. High rubber content.