The Schwalbe 700C SV15 butyl rubber bicycle inner tubes are the best . They are are made of thicker butyl rubber than standard tubes and therefore hold air for longer. I've found I only have to add air every couple of months, and I use the bike every day . Used in combination with Schwalbe Durano Plus tyres with high puncture resistance, its a winning combination . They cost a little more than standard tubes , but the reduced maintenance with not having to pump them up all the time is great. I run my tyres at 100 PSI and I dont need to recheck the pressure every week.
A quality product. Does the job better than most.