Easy, secure, one-handed fitting The Zippey Trolley is bi-directional, so there’s no wrong way to fit it. Zippey offers a one handed action there’s no wrong way to fit it. Zippey offers a one handed action with increased safety. The simple, yet secure spring-loaded double locking gate mechanism can be easily operated with finger or thumb. The gate mechanism features a twin keylock (anti-snag) nose for strength andsecurity. The gate closure is effected by a standard Stainless SteelKarabiner gate spring, ensuring a smooth, positive and long-life action.