These are 4x1" Button Head Sheet Metal Screws by Du-Bro.

Features

Zinc plated metal construction with clear chromate.
Non-slip socket drive insert.
The large head of the screw acts as a washer.
A new design that's great for mounting servos, cowls, landing
gear, etc.

Includes

(8) Screws

Specifications

Length: 1"
Diameter: 4mm

Comments

This uses a 1/16" size allen wrench (GPMR8006)