States in reference given:
158mm long x 64mm wide x 53mm high
Agreed not the smallest or lightest, but OP wanted a pump that "works
well
with road and mountain bikes" and with a gauge.
"Easily the heaviest" - yes, but not outrageously so. A standard
Blackburn full size frame pump is quoted as "Weight for shortest
length: 247g" so 302g is in the right area.
My experience with mini pumps is that they are a pain, taking too many
strokes to get to a decent pressure.
This one fulfils OPs requirements.
As a touring/commuting cyclist I rarely travel without some sort of bag
or panier, this pump is much easier for me to carry than a traditional
(long) pump.
Like many things, it depends on your requirements. This suggestion is
portable and could be your only pump (though I already have a track
pump at home). It won't suit everyone, but it's good to have a choice
of different types as well as different manufacturers.
Andrew Webster