This kit includes everything required for upper cabinet microwave installation: a 1/4"-28 UNF fine-thread 3-inch bolt, broad load-distributing washer, and a matched-size drill bit for preparing pilot holes. It is engineered to replace common factory screw part numbers including: WB01X10180 (top mounting bolt used in many microwave/hood installations) DE60-20066A (fine-thread flat head bolt used in over-the-range installations) 5304456138 (self-aligning microwave mounting screw) The 1/4-28 thread matches internal nut plates in many upper-cabinet microwave models. The included washer helps prevent cabinet panel damage, while the drill bit ensures proper hole sizing. This kit is ideal for reinstalling used microwaves, replacing lost screws, or ensuring safe mounting during new installations. Confirm thread pitch before purchase: this kit is for fine-thread (1/4-28) installations only.