Condom size. This is from condom sizes.org: "Quick Tip: if your penis girth is below 4.7 inches (119mm) check out the snugger fit section. Regular condoms will best suit you if your girth is between 4.7?–5.1? (119-130mm). Guys with girth bigger than 5.1? (130mm) should use a larger condom." See: http://www.condom-sizes.org/condom-size-chart/condom-size-chart. Don't just guess.
Depends. I wold buy an assortment package off the internet and try them out! some like a loose fit, some like a tight fit. Some like latex, some like a plastic type comdon, some like the sheep intestine feel. You have an average size phallus in length with perhaps a bit larger girth. Try them out an see what you like. Best advice? Just use one you will wear and wear it! be responsible to all.