Bomar Riser Arm For 100 Series Hatches . With these spare parts for your Nibo or Gray hatch you can replace worn or damaged parts for a fraction of the cost of replacing the hatch. Low-Profile Gasket in a 9 length 916 Gasket in a 10 length Available for the 100 series Riser Arm Male Hatch Knob Female Hatch Knob Hatch Tiedown Dog Left-Locking Quick Dog Right-Locking Quick Dog