All of these universal wall mount brackets listed on the page below are compatible with Insignia NS-55D420NA18 55" LED TVs. All Star Mounts carries various types of mounting bracket solutions such as flat (fixed position), tilting and articulating (full motion, pivot, swing).
Insignia NS-55D420NA18 wall mount bracket requirements:
Fit VESA 200x200mm mounting holes on back of the TV
Support 36.8 lbs (weight without stand)
TV dimensions: 49.0" x 28.4" x 3.3"
Note: As always when attaching a bracket to the wall make sure that the structure attaching the wall plate to can handle the load being applied to it based on the wall mount style you choose to purchase.