e glue they use its kinda rubbery so you can remove things if u need to replace them but strong enough to hold the retracts in place.
2nd I was wondering about electric retracts, i love them so far does anyone out there make electric retracts for larger scale jets like the F-16 or F-18?
Hobbyking has electric retracts for models up to 3.6 kg. Go to their site at
http://www.hobbyking.com and search for 'dsr' and you will get a list with products. You can find the search box under the category list at the left.