550kg High Torque RC Servo, 2 in 1 Servo and Motor 16V~24V High Voltage Full Metal Gear Digital Servo

The difference between the s350 and s550 is the planetary gear ratio. I use both of these. The S550 is slower but has 57% higher torque. The mounting holes are the same. Electrically they are similar. The power connector on the s550 is capable of higher current and is an improvement over the 2.54 mm spaced pins on the s350. My application needs two of the higher torque units, but the final drive gears failed on one (per mfg specs, the motor torque limit should have prevented this). Amazon immediately replaced the bad unit.

Great servo and accessories and support. The design and execution and support are amazing. Support engineers are very responsive. The documentation is good.

Bought this for a holding mechanism that needed precise control - and the ability to have usefulness in other areas (servo or regular motor). What a great product and excellent seller! Definitely watch the video on the last image of product description (explains light codes, setting, etc). Also, note that for direction control in motor mode, use PWM with the following logic:0-49% = motor goes forward50% = stops (holds position)51-100% = motor goes backwardsUse direction toggle to switch these.Great value for the money. Will continue to be useful and last a long time.Seller also responds quickly to emails - so don’t hesitate to contact them with questions!

I have three of these servos, and they're very, very powerful. Crazy amounts of torque, and easy to set up, overall. The physical design is nice, with good placement of bolt positions. Pretty accurate in positioning, too.I wish they had a different and more-rugged power connector, though.One caveat: They're powerful enough and fast enough to be moderately dangerous. Make sure to stand clear of them and _keep your hands away_ when they're powered up. You can limit their arc and initial position easily enough, but if you moved the controller position while they're turned off, they'll go to the new position right away, at full speed and power. I ended up including some physical stops for the lever one was driving, and used a belt drive (that can slip some) for another.For the price, you won't find another servo with more power and features, especially in this form factor.

Wanted more power, I believe they sent me a used one had scratches all over it, returned it and got the more powerful one, works great

I am building a large (5 foot tall) robot for Halloween and needed a way to rotate the head (a 16" plywood cube). This easily handles the job and is far more powerful than the strongest 1/5 hobby RC servo that I could find at double the price. It also has a D-profile 8mm output shaft which is much better for high torque applications than a 25T RC servo output. I really like the manual potentiometers for precision adjustments of center point and range. Mounting this is easy as well. Lots of holes with pre-molded nut retention, etc. The plastic housing I believe is glass reinforced nylon so is very strong.

I'm very happy with these servos but there are a few things worth noting.First is the speed.I've used a lot of much smaller servos before and typically they aren't very fast, these servos on the other hand are extremely fast, do not get in the way of whatever you have connected to them!To slow them down I had to inject delays between pulses like this...void loop(){for (int i = 200; i < 400; i++){pwm.setPWM(0, 0, i);delay(10);}}This works fine and allows you to fine-tune the speed by playing around with the delay value.Second, as previously mentioned in another review the power connector is reversed from the standard config. No problem if you are building your power cable but if not it could be a serious problem.Third, the power connector they use works great but it adds maybe 5 or 6mm of overall height when the power cable is plugged in, something that wasn't mentioned in the ad or reviews that I saw.If you have plenty of room above the servo it's not an issue but in my case, I had to get creative to make the servo fit in the space I had available for it.Lastly, another reviewer stated that the mount used non-standard hardware, on the two that I received the mounts used standard M4 hardware. They did however allow for M4 nuts to be used on both ends of the mounts, if you use M4 bolts this might be fine but I use M4 button head screws and had to put M4 washers under the screw heads to keep them from being pulled into the mounts.These small issues are why I gave them 4 stars instead of 5.

Great for robotics on a budget, make great MVP.