In conjunction with a 8m retractable lead, I can give him the freedom to snuffle round in bushes, withou letting him loose - or to keep him in close when people or other dogs are around.
Tip for retractable dog-lead users. — Digital Spy
Name:(10 Pieces/Lot)Top Grade 8M Length 40Kg Weight Pet Leash Automatic Strong LED Dog Retractable Leash Lead Material:ABS Size: 8 Meters Length and 40kg Weight Color: Black/Blue/Red
How To: Retractable Flexi Dog Leash Dismantle and repair - YouTube
I always use a harness for walking though - I never let him loose in public, so I use a 8m retractable lead to give him some freedom around trees/bushes etc - You really HAVE to use a body harness with one of those, in case the dog suddenly comes to the end of it's travel, attaching to a head or neck collar would carry the risk of neck damage.
Does your Labrador always run away from when your going for a walk