yeah, i think butterfly & trekking are the same, but there are many
varieties and shapes available. the ones i tried were about 60cm
wide, but with the inwards curve, put the center of the grips spaced
at 42cm. too close to be comfortable, and didn't feel like i had the
leverage i wanted on rough surfaces. i dinna use the tops, just
the grips and sides, so kinda pointless really.

originally had 70cm wide mtb bars, which migrated to another bike.
have replaced with 64cm flats, center of grips measure 48cm.
even that feels a little tight, 66 would prolly have been better....