Basically anything that has the proper width in the back of the saddle, doesn't have too much cushion (I think maybe 10mm is the max cushion I'd want), and most importantly, is installed correctly, with the reach to the bars, the angle to the pedals and the tilt of the saddle correct. You can wind up sliding off the wide part and putting pressure on the narrow bit of the saddle if any of those is wrong.
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Work: the 8 hours that separates bike rides.