I run no give rotaries, Nicks, Dan Kubins etc etc...I am aware of the slight advantage of using softer gromms to offer some dampening, or put another way, to help soften the force of hit ....I came across these.....Trust me, if you run no give Machines, you will enjoy these... http://www.ebay.co.uk/itm/1307317256...ht_3278wt_1097 this is the Europe Shop, he also has a USA Shop...Please no haters just cos it is from ebay......