For 1 1/4” Square tube bimini frame, opening on the bracket fits 1 1/4” fence rails (can be used on 1" fence rails as well with a 1/8" gap on each side). Regular H brackets raise the hardware 1 1/4" above the rail and was used as the standard bracket of most bimini frames for years. Heavy Duty aluminum brackets with stainless steel hardware. 4 brackets w/ hardware to attach to the fence rail. Quick release pins not included but can be purchased in our store as well if needed.