The rubber dust cover is made by high quality silicone rubber. can be used to SFP. Color is black/white/red/blue,etc. Also accept customized size too. Besides the rubber dust for USB A, we have rubber caps and rubber plugs for RJ45, DP,DIV,SFP, RJ11,MICRO USB PORT,TYPE-C, RCA,HDMI.AUDIO-A,AUDIO-B,DB-9,VGA,RS232, IETS,SD-A,BNC,AV,EX1R,DDR123, SD-E,PCI,PCI-E,AGP,USB-B, MINI USB, ETS MICRO HDMI,SFP-B, MINI DISPLAY PORT,DB25,LPT,ESATA-A,FIREWIRE800(1394-9),ETC.