Experimental results on the flipping efficiency are shown for a set of 2 V-coils as spin flipper and for a high-frequency flipper with adiabatic transition. The influence of the adiabaticity parameter is discussed. The merits of these adiabatic flippers are compared with the use of "monochromatic" flippers, when operated in a beam from a pulsed neutron source. It is concluded that for "long pulse" sources adiabatic flippers will be superior.