My young cat got lost and someone found him and took him to the city animal shelter. Luckily, I had taken some photos of him, so the shelter called me the next day. Now he doesn't run loose. He is either in the house, in the 8 ft X 20 ft outside pen, or I take him walking on his leash. The buckle on the leash I bought was difficult to fasten and unfasten and he would get upset that I was doing it too slow.
I ordered a magnetic catch listed on eBay in China for $1.00. I used epoxy glue to attach a leather strap into the holes of the magnetic clasp after sewing another piece of leather to hold a "D ring" to snap the leash onto. The magnetic clasp is very fast and secure. I have used it for almost a year and it has never accidentally come loose. The one I bought has magnet to hold a cross piece into a slot, making it impossible to pull loose until I lift one end. I could not find this exact one listed on eBay, but there are several that are very similar. Just search on eBay for "magnetic clasp". As for ordering from China, I have found the Chinese vendors very reputable. Shipping usually takes 7 to 10 days.