The Parallax Pre-Modified servo motor is a good choice for simple experiments and driving motors for lightweight robots.

The pre-modified servo comes modified for continuous rotation, having a brass load bushing to shoulder the load, which is much better than a plain plastic-bushing found in economy servos. Putting the weight of a robot on the side of a servo can eventually wear down the servo, but this brass bushing does a great job of taking the load.

Specifications:

• Power: 6vdc max
• Average Speed: 60 rpm (5V, no load)
• Weight: 45.0 grams/1.59oz
• Torque: 3.40 kg-cm/47oz-in
• Size mm: (L x W x H) 40.5×20.0x38.0
• Size inch: (L x W x H) 1.60x.79×1.50
• Manual “zero” adjustment port for fine-tuning