55g each.

They are MTB skewers primarily which are designed for 135mm rear hub spacing so will be 5mm longer than a road skewer, other than that they should be fine.

Generally we have the new style square ended ones. Worth mentioning in the order note section when you order so the processor will double check and ensure you are sent the ones you require.

Without knowing the make and model of the bike I can not say.

Sorry we do not stock specialized bikes so I would advise contacting them directly, but likely they will be fine.

The Front quick release skewer is 100mm in length. The rear skewer is 135mm in length.

The rear axle length on a Dahon Cadenze Solo is 130mm so you can use standard Quick Releases in your hubs. yes these will fit.

Unfortunately not, the genesis flyer uses a 122mm nutted axle so you can't use these skewers.

The Giant XTC Junior 24" uses bolt on hubs which do not accept a quick release so unfortunately these QR's will not be suitable.

Yes you can use these skewers on the Focus First