http://www.infinity-hobby.com/main/product_info.php?products_id=10786
The vibration isolator is equipped with M3 screw holes to fit common needs. Each vibration isolator V2 can be assembled with 2~6 O rings (6 at most). For user’s choice, there are two kinds of O rings, orange one with hardness 75 and blue one with hardness 55. Please select according to your preference and purposes.