If you want to trolling for salmon or trout fishing, you don't have a downrigger . You need the plane. If you have a kayak or a small boat. You don't want to set up the downrigger on your kayak or small boat so You need the right size plane for your trolling fishing. Diver Trolling https://www.leeroysramblings.com/Diver_Trolling.htm Right now I ave 18 planes for sale. 5" plane for $ 20.00 each retail new one for $44.99 plus taxes. 4" plane for $ 15.00 each retail new one for $ 39.99 plus taxes. 3" plane for $ 10.00 each retail new one $ 23.99 plus taxes The last picture, its 3.5" for $ 22 USD plus shipping for $12 USD total is about $47 CAD . All prices FIRM.