11/32 is that universal size on some atf cooler kits. By all means, by the 3/8 ATF hose from just about any autoparts store.
That universal size makes it easy to fit ATF coolers on multiple cars since some use 10/32, 11/32, or 12/32 fittings. For those that failed math, 11/32 will work with 5/16 and 3/8 fittings. But, 3/8 hose is easier to fit(use silicone spray lube on the fitting if you're limp wristed).
I never cared for ATF cooler kits(or engine oil filte rrelocation kits) that used smaller hose diameters. Smaller hoses add to flow restriction.