Very good value and installed with no issues - Guntec USA 4in Ultra Lightweight Thin M-LOK System Handguard w/ Monolithic Top Rail

Here are some tips and details about this product that I wish I would have known before purchasing:

Finish quality is very good (no rough edges or burrs anywhere on the handguard)
It is narrow and very light--as I expected and wanted.
Mounting screws definitely need blue loctite when assembled
Barrel nut on mine was aluminum with 32mm wrench flats. It fits under the gas tube with no issues.

I bought a 1 1/8 Sunex crow's foot on Amazon for $9 and used my bench grinder to enlarge it to 32mm. I also had to grind it thinner to fit on the barrel nut's flats.

I torqued my barrel nut to 50ft-lbs with silver anti-seize on the Aero Precision upper receiver threads to get the nut timed properly for the handguard to mount. I also used 3 of the included shims.

The holes in the handguard are slightly oval so minor adjustments can be made to its position. It was not difficult to line it up with my upper receiver's rail.