Thin wall cable
Tinned thin wall single core cable in 4, 6 and 10mm². The insulation is thinner than standard PVC, so the finished cable is smaller overall and easier to pull through a conduit or a tight gland.
Suits lighting, pumps, fridges and instrument runs rather than main battery feeds. For anything carrying real current, use battery cable.
Note that no lug is made small enough for 4mm², so that size is sold cut to length with bare ends only.