Basic pay for GS employees is a position's annual salary plus any other applicable civilian employee pay entitlements. Basic pay for FWS employees is a position's annual wages including shift differential pay and environmental pay, plus any other applicable civilian employee pay entitlements. Examples of other civilian employee pay entitlements include, but are not limited to, night differential pay for FWS employees, environmental differential pay, and premium pay (for civilian employee fire fighters and law enforcement officers).