ACCESSORY INFORMATION The VideoRay Crawler attachment is so simple and effective it's ridiculous. It has been specifically designed for the Pro 4 Float Block and is an essential attachment for obtaining stable video on submerged surfaces in difficult, high current underwater Ideal applications for the VideoRay Crawler attachment include ship hull inspections, potable watertanks, and any submerged structure with a rigid surface. The hull crawler attachment will not work on VideoRay Pro 3 float blocks. This no-tools-required accessory easily attaches in seconds - put it on or take it off as needed in the field and start inspecting. No "mastering of roll techniques" are required to adhere to a surface - simply get under the surface and use the powerful suction of the ROVs vertical thruster to latch on and roll effortlessly upright while obtaining stable video. Imagine trying to flip a submersible over with thrusters in a 5 knot current and zero visibility. By the time another submersible "masters the roll," the VideoRay Pro 4 would be half way done with the hull inspection. The VideoRay Crawler also does not use magnets for obvious reasons [think explosive device on a ship hull). The powerful VideoRay Pro 4 vertical thruster is ducted to move water away from the hull causing zero disturbance while latching upright and in a familiar operating position for the pilot. BASIC CRAWLER SPECIFICATIONS Total Accessory Weight: Depth Rating: Attractive Force: Operating Conditions: additional ballast