Polaris 360 BlackMax Replacement Inline Back-Up Valve - Black. Be sure to check the size of your hose before ordering this back-up valve. The Polaris 360 has a larger corrugated hose close to 1.5" in diameter. If your hose is smooth and about the size of a garden hose then you have a Polaris 380. Check related products before for the 380 version of this back-up valve. As always, contact us if you need any help.