They help a bunch...nice to hold an object with both hands while looking at it..
Great pin pointer from Garrett and Metal Detecting Stuff is my #1 source for products. Excellent service
HPI Racing #1450 is a dust protection and O-ring replacement set for one Nitro Star S-25 engine. HPI lists a rear cover O-ring (20 x 22.5 x 1.25 mm), an O-ring (5.5 x 8.5 x 1.5 mm), two carburetor O-rings (10 x 12 x 1.0 mm), and a main needle valve O-ring (2 x 5 x 1.5 mm).
Check the engine model and part number before ordering; HPI identifies #1435 for the 21BB engine.