Cleats
The standard “sneaker” type shoes players wear on game day. Teams designate a color for each game, typically black or white, and all players must match that color. Players may choose to wear a brand and style of shoe that has been approved by the league, or he may wear a different shoe if it is the same color as those worn by his teammates. Kickers and punters cannot modify their shoes to gain an unfair advantage when kicking the football.
Facemask
The cage on the front of a player’s helmet that helps protect a player’s face from unnecessary risk of injury. Tackling a player by grabbing his face mask is forbidden and results in a 15-yard penalty.
Helmet
The equipment worn on a player’s head to help protect him from unnecessary risk of injury. Helmets were once made of leather and lacked protection for a player’s face. Today’s helmets are made to the highest safety standards possible. All styles of helmets must be approved by the league.
Jersey
The designated shirts a player wears during NFL games. Jerseys must cover all of the pads and protective gear he wears on his torso and upper arms and must display the player’s last name and number.
Jersey numbers
Every player is assigned a number, which has to appear on the front, back and shoulder or arms of his jersey. The NFL assigns numbers to players that align with his playing position to help game officials make sure that every player is lined up properly before each play.
- Quarterbacks, punters, and placekickers: 1–19
- Running backs and defensive backs: 20–49
- Centers: 50–79
- Offensive guards and tackles: 60–79
- Wide receivers: 10–19 and 80–89
- Tight ends and H-backs: 40–49 and 80–89
- Defensive linemen: 50–79 and 90–99
- Linebackers: 40–59 and 90–99
Pads
The NFL requires every player to wear league-approved shoulder, thigh and knee pads under his uniform. Punters and placekickers may omit thigh and knee pads.
Uniform
An NFL uniform includes all of the equipment a player wears on the field. This includes his helmet, pads and all protective gear, pants, jerseys, wristbands, gloves, stockings, shoes, undergarments and accessories like hand towels that are visible when a player takes the field. Every part of the uniform worn on game day either must be issued by the club or the league, or approved by the league.
Source: NFL.com