Here is the info about the Snow Speeders

Whilst on Hoth, the rebels modified these T-47 airspeeders to cope with the planet’s frigid climate. Mainly used for patrols and the defence of Echo Base, these fighters carry a two-man crew – a pilot and a rear-gunner. They also come equipped with two laser cannons and a harpoon gun. Fast and highly manoeuvrable, the snowspeeders are the rebels’ answer to the Empire’s hulking AT-ATs.