The Spider was originally designed by Newhart Industries as a 'Mech to be used by SLDF commando forces. The 'Mech gets its name from the unique pattern on its chest that radiates from the Medium Laser mounts in its center torso. The Spider is one of the most maneuverable BattleMechs ever conceived. It has a ground speed that is comparable to a Locust and can out jump either the vaunted Wasp or Stinger light 'Mechs. Spiders are generally used as fast strike forces to hit an enemy's rear with lightning speed.
The Spider carries a very light armament of two Aberdovey Mk III Medium Lasers. The lasers are marginally effective against other 'Mechs and hard targets but are more then effective against soft targets such as ammunition crates and command posts.
- SDR-7K - The 7K is an upgrade of the design that uses a Light Fusion engine in place of the standard model. It carries two Medium Pulse Lasers and is built using an Endo Steel structure and Ferro-Fibrous armor.
- SDR-7K2 - the 7K2 is built using an Endo Steel structure and Ferro-Fibrous armor, it has reduced its jump capability to only 210 meters but now carries an Extended Range Large Laser
- SDR-7M - The 7M upgrades the internal structure to an Endo Steel version and upgrades the armor to Ferro-Fibrous The saved weight is used to upgrade the standard Medium Lasers to Pulse Lasers.
- SDR-8M - The 8M is a simple upgrade of the 7M and replaces the single heat sinks with double strength versions. Otherwise they are completely identical.