Hi Christopher and welcome. 35.75 inches fully extended and 32.5 inches when fully collapsed. Cheers, stay safe and enjoy!

32.75"-35.25" ******
Diamondback Firearms DB15 AR-15 Specifications and Features:
Diamondback Firearms Item Number: DBK1717K005
AR15 Semi Automatic Rifle
Direct Impingement
Carbine Gas System
5.56 NATO (Also Accepts .223 Remington)
30 Rounds
16" 4150 CMV Barrel
1:8 Barrel Twist
A2 Flash Hider
1/2x28 Thread Pitch
7075 Aluminum Receivers
Mil-Spec Trigger
M4 feed Ramps
15" M-LOK Free Float Handguard
Magpul Collapsible Stock
Magpul Pistol Grip
********Overall Length 32.75"-35.25"
Weight 6.8 lbs
Black Finish

Hi Christopher, Overall Length: (Stock Collapsed 32 1/2″) (Stock Expanded 35 3/4″)
Stay safe & have a great day!