I think there was some patent/licensing issue or somesuch, so they aren't included by default on the Naish bar. They do sell it separately ($10), and it works when you want it. I've never had an issue with it sliding down. I don't know about other brands though.
In addition to allowing you to do silly stuff (great points edt ), I like to set it on a long tack to relieve my arms.
You need a stopper to do any variation deadman, or any kind of move where you do a board off and pass the board around your body. You can also use the stopper to play air guitar, point both your fingers into a gun shape and do a double handed air gun while you go "Pow pow pow" with your mouth, and scratch your nuts with one hand while you twirl the board like a baton with the other. They have a lot of uses.
Looks like I need to up my double handed air gun game!
I also use them as another trim. Might because we learnt on two line foils with no trim, but a totally depowered kite is a shitty kite.
Set the trim using your normal cleat, then a secondary trim using the stopper, giving you the travel you need to optimise the trim level required given gust factors.
You need a stopper to do any variation deadman, or any kind of move where you do a board off and pass the board around your body. You can also use the stopper to play air guitar, point both your fingers into a gun shape and do a double handed air gun while you go "Pow pow pow" with your mouth, and scratch your nuts with one hand while you twirl the board like a baton with the other. They have a lot of uses.
Local Beach: Wijk aan zee, Zandmotor, Hoek and in between
Favorite Beaches: Muriwai NZ, El Medano Tenerife, la Ventana México, Hood River, Portland area, Vancouver Island, Wijk aan Zee, Moulay Bouzerktoun
Style: Waveriding
Gear: RRD Religion 4 meter, 5 and 7 meter Kauper XT Maverick, 9 meter Core GTS6, Ben Wilson Vibe 9, Peter Lynn Phantom v2 9, Appletree Klokhouse Noseless 5'3", Wanted Pure 6'0", Shinn Bronq Heritage, Gong Foil