for obedience work/training i use martingale collars which are nylon and chain (and a correction chain on the chihuahua but not to correct he will only work weariong the chain )

for walking i use nylon harnesses for the 2 lil dogs (penny the JRT X can still slip out of hers Grrrr) and clover wears a halti collar when walking on lead or just a normal nylon collar or her martingale for playing at the park (and nylon harness for flyball)