Zyltech 'brand' stepper motors?

Noob looking for a little help with new stepper motors. I found some NEMA 17 steppers that seemed good for the price, if they are any good that is. 1.7amp 59Nm (84oz in) holding torque, $30 for 3 with free shipping from Amazon. So I bought 3 of them for my first Delta build (Kossel Mini).

The spec sheet that comes with them says Zyltech Engineering, a website that comes up searching the name Zyltech indicates they are a Houston Texas based engineering company.

Spec sheet says this about the motors:

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2 phase

1.8 step angle

5% step accuracy

59Nm Holding Torque

1.7A/phase rated current

82G-cm Rotor inertia

1.8 ohms Phase resistance

3.06 V rated Voltage

3.8 mH +-20% Inductance

100 MΩmin (500V) Insulation resistance

Class B Insulation class

406g Weight

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Does that all seem correct for a 'normal' NEMA 17?

Has anyone used this company's products?

How can I test them to verify the product to help others decision making? I will be googling this and searching it as well, if it is a pain in the butt to answer don't worry about it. But I could find no posts through google on any forums about the company Zyltech so I thought I better raise my hand and ask about them... since I sorta took a gamble and bought them!

Here is the link:
Zyltech Steppers 3 for $30 on Amazon

Any info would be helpful, I am new to this. Thanks for reading

1. That inductance seems a little high.. but otherwise they look good to me,
2. Don't forget about the extruder stepper depending on if extruder includes one.
3. Make sure you have decent electronics to push 1.7A, cheap Chinese DRV8825 should cap out somewhere around there
4. Another great post about motor size

Hope your delta build goes well!

Thanks for the link, very helpful!