Pick any two letters for your set of magnets. Popular choices are initials or an "X" and "O" for Love & Hugs. Buy a set for yourself and buy a set for your boating friends. All magnets are approximately 2" square. The magnets that I use are strong! But your refrigerator and my magnets may not be kid proof. What can I say? If they fall off your refrigerator, they will most likely break because they are glass! Spell anything and Say It With Glass.