@ Akhor
Are these a direct fit on the Losi air filter hanger?
Yep - the Losi filter set up is a pretty good one which we could not improve on as its so well intergrated. These foams are a staright fit on the stock Losi filter set up.
@ New One
One question though what is the best lubricant for the Answer bearings.
In terms of a lube - it really depends how you like it. If you are pulling seals off and re lubing a grease is the way to go as it wont get thown so easily, otherwise a good oil perhaps a little thicker than 3in1 is the way to go. I dont have my data sheets to hand but will find what we specced in the original data sheets for them.