How to Know the Operating angle/Range before I buy a servo, if the only info given on the site is:
Operating Voltage: 4.8- 6.0VDC
Operating Speed: 0.20sec/60degree (4.8V), 0.16sec/60degree (6.0V)
Stall Torque: 5.3kgcm (4.8V), 7kgcm (6.0V)
Temperature Range: -20°C ~60°C
Dead Band Width: 4ms
Dimension: 41x20x38mm
Weight: 41g
Cable in Length: 30cm
Its just like any other purchase, ask the seller for any details or choose a different seller who has provided the info...
In addition to what @MarkT has said, what operating range do you need?
...R
Typical servos move through an angle of about 100 degrees for a pulse width in the range 1ms to 2ms. Most low cost analog servos will operate over an angle close to 180 degrees by driving with smaller ang larger width pulses. You will find discussions on this topic on many robotics web site forums.
Digital servos, in particular powerful brushless ones, tend to have a constrained angle and only accept pulses in the range 0.9 to 2.1ms to stop them hitting the end stops and becoming damaged.
There are also servos especifically designed for robotics that operate through an angle of at least 180 degrees for robotic arms.
You may find the info you want at the servo database.
I use MG996R servos, they lack precision but are robust with metal gears however there are a lot of "clones" about with the same part number which has given them a poorer reputation than they deserve. SG-5010 servos work well on light loads (plastic gears) but again lack precision. There are many Futaba clones/fakes about so watch out for that. For more precison I like Hitec servos.