Jabsco SK880 Service Kit for 50880 Diaphragm Pumps 504485 Warning Lights This would mean the boom Size::F1 This would mean the boom position may not be correct but will allow you to measure the downward force required (with sail flaked) on the aft end of the boom to flex the rods These Narrowboat Pipe Fenders are made from solid rubber with an internal nylon rope which runs through the fender core and has a looped eye at one end for positioning the fender onto a narrowboat Brand Jabsco Model SK880 Suitability Jabsco 50880 1000 & 50880 1100 Diaphragm Pumps Contents See Description decorateTable('product attribute specs table') Jabsco SK880 service kit for Jabsco 50880 series diaphragm pumps: 50880 1000 and 50880 1100