... weather resistant, good insulation property, anti-toxic, good air-permeable silicone rubber o-ring for toys, etc.4. Hardness: 20-80 shore ... : strictly upon international standard, and no flash.7. Color: black silicone rubber o-ring for toys, transparent, green, red, yellow, grey, ... with ISO9001:2008.2. QC/QA: we have strict quality control and assurance system.3. Compression machine: 11 sets, from 50 ...