The Slip oiler pen gives easy access to bearings with a 1" (25.4mm) steel tip which is protected by the plastic cap. It holds 1/4oz (7.4cc) of oil which should last you well over a year of racing.
Oil can be used on wheel and clutch bearings. If you want to prolong the life of a clutch bearing Avid suggests that you blow out the grease of the bearing with an air compressor and use the bearings just like this for the first 1/2 gallon. This leaves a slight layer of protection to the bearing and then each time you take your motor out to check the clutch shoes, you should wipe down the bearing to remove any dirt collected on the outside and then add 1 drop of Slip Bearing Oil to the bearing before putting back into the clutch.