A Girder is a long thin piece of metal platform that can be placed anywhere nearby the user. The Bridge Kit offers five of these Girders.
Once placed, the Girders have no special properties over the rest of the terrain. It is usually used by players to make a piece of platform to prevent their Worms from slipping into the water, or to create pathways, but is most often used to protect the player's Worms from incoming threats, or block the opponent's Worms.
In Worms 3D, the Bridge Kit is unlocked in the Campaign Mission "Beefcake Breakfast Brawl" - on the roof there is a Utility Crate on a platform. Low Gravity must be used to reach it. Collecting it will acquire the Bridge Kit in the mission and unlock it for use in multiplayer.
Get out of this!
The Girder Starter Pack is an absolute godsend in a situation where immediate return fire simply will result in your doom.
Carefully plotting this handful of Girders can make the most secure of Worm defences leaving only small gaps to launch.
Another method of use for the Girder Starter Pack is to block in the enemy Worms if you can get close enough to your adversaries.
Remember to ensure that the enemy cannot move without wasting a turn by using a weapon and that you can damage them by making full use of the blast radius from weapons such as the Bazooka.
Placing the girders in a tunnel like shape towards the enemy can provide an excellent shoot to provide the correct path in which the Grenade should travel to accurately reach your target. Don't forget to move your Worm out of harms way once the tunnel has been created because where there is a way out, there's a way in!