you can also by the cheaper but way better hunter pgp. they sell what is called a "checkomatic". it is what is in the hunter i20. its just a replacement screen with a rubber washer. unscrew the heads guts, pull out the screen, replace with checkomatic screen. done. if you do get the more expensive I20 heads.....stay away from the stainless steel variety. i cant stress this enough. i would never put them in my yard. and i have been doing this for 15 years.
