Short Schrader valve cores. Set of 2 (Ref:22) - CXB08534
Very often the cause of a slowly deflating tyre is a defective or loose valve core. Check for leakage by applying a wet finger over the valve (soapy water is best, but spit will do) and if you get a bubble, the valve is leaking. Tighten, using using the 4in1 tyre tool above, and if the leak persists, change the valve core.