Bore Guide #59 Browning L70, Sako A3, A4, L61, Finnbear 491, 591, 691, Howa 1500, Tikka 595, 590, 695, 690, and Weatherby Vanguard Bore Guides are 100% solvent resistant. Bore Guide is machined with a snout that extends into rifle chamber. Silicone "O" ring that seals off chamber. Aligns the cleaning rod with center of rifle bore. Insures no damage can be done by a jag or a brush while cleaning.