Here's a superb, engineering quality siphon pump with a firm rubber bulb with an internal valve.

Inlet and outlet is a machined aluminium, 8mm diameter barbed hosetail.

Flow direction is clearly marked with an arrow on the bulb.

Overall length 150mm.

Bulb diameter 44mm.

Weight 75gms. 

PROFESSIONAL SIPHON PUMP FOR 8mm HOSE #PROSIPHON