There are two main types of K&N filter cleaning kits.
99-5000 which uses an aerosol for the filter oil
& the 99-5050 which uses a squeezy bottle for the oil.
The 99-5000 sprays the oil onto the filter, the 99-5050 you have to oil each pleat individually. Personally I prefer the 99-5000, its much less labour intensive and quicker
Buy the 99-5000 cleaning kit on ebay UK here
Buy the 99-5000 cleaning kit on ebay USA here
Buy the 99-5050 cleaning kit on ebay UK here
Buy the 99-5050 cleaning kit on ebay USA here
Both kits come with the same bottle of shampoo for the filter.
On an average sized &N air filter there is enough product in the kit to wash and service a filters many times.