Look for Leviton outlets/GFCI's that are marked WR. These are commercial
grade. I use only 20 amp outlets.
Leviton’s line of Extra Heavy-Duty Industrial Grade receptacles are designed and manufactured to withstand the harsh conditions typically associated with industrial environments. Available in a wide variety of configurations, including isolated ground, tamper-resistant, hospital grade, etc., these Industrial Grade devices are the electrical
contractor's choice for use in factories, schools, hospitals and commercial
20 Amp, 125 Volt, NEMA 5-20R, 2P, 3W, Wide Body Duplex Receptacle, Straight Blade, Industrial Grade, Self Grounding, Weather-Resistant, Back & Side Wired, Nickel-Plated Brass Strap - WHITE
Full Specs here.