"It's simple: The BeatDown Outdoors The Ultimate Sonar Mount represents the industry's best combination of convenience, durability, and versatility. With the patented reverse-telescopic design, it's the only mount on the market that lets you see your graphs from the deck of your boat all the way to 30""H with the twist of a knob, giving you the most visible picture for whatever height you need. Oversized knobs mean easy adjustment in any conditions, even through thick gloves. 6061 aluminum 304 stainless BeatDown Bi-Metal construction provides amazing smoothness and strength. Includes under-deck plate 6061 aluminum 304 stainless Beatdown Bi-Metal construction Patented reverse-telescopic design extends from deck of floor to 30""H Patented locking collars easily use your graph at any height up to 30"" Oversized knobs"