700 x 23c Racing bike solid tyres.
Material: Polyurethane .
Tubeless. So no inner tubes needed, and of course you will have no punctures (ever).
They are very tight fit, and ideally suited to double wall rim wheels. They sell for approx 13 quid each (see picture).
These were originally bought for a customer who was doing a charity bike race. I installed them for the customer to try, but then removed them as customer found the ride a bit hard. Customer had to choose between a hard ride, and no punctures or a softer ride on conventional tyres and risk punctures on a long road race!
Therefore tyres are virtually new aside from a bit of dirt from off the road through road test.