These are absolutely the worst leads I've ever seen.  They prove that the "cheap overseaas" moniker is deserved and --astoundingly-- devolving.  The wire is maybe 28 AWG, _maybe_.  It's uncoated copper, pre-corroded (turning green/black).  The plastic coating is a bit rougher (which initially seemed nice, versus the previous el-cheapo leads with shiny plastic coating).  The clips are of course awful.  The clips are crimped (not soldered) onto the wires and coating, with the bared wires folded back over the coating...meaning that simply "adding a dab of solder to the crimp" (which used to work on all previous el-cheapo leads) no longer works and instead causes a molten, stinky plastic mess.