Hatsan AT44-10QE Fill

Assuming that your hand pump has a female foster fitting on it, you need a male foster adapter for the Hatsan fill probe. Pyramyd Air (or the airgun retailer of your choice) has them. Pyramid Air part number PY-A-3550. It is the 1st item listed when you go to their PCP accessories / fittings page. Or use their search with the part number. It is around $10 I think.