Sinclair solvent ports permit the user to apply solvent to a brush, patch, or mop without getting it all over the rifle or their work area. Our solvent ports plug into the end of your Sinclair cleaning rod guides and seal with a silicone O-ring. Each solvent port has an opening where you can apply solvent directly onto the cleaning implement being used. One size port for .17 caliber thru 6.5 mm rod guides, a second size for .270 caliber up to .30 caliber and a third size for 8mm and 338 caliber. These solvent ports will fit all Sinclair Rod Guides except for RG4A54 and RG4A5417 rimfire guides.