Meet the FLEX FX4521-Z 3/8" Stapler — a cordless, brushless stapler built for pros tackling Tyvek wrap, carpeting, and other fastening jobs without dragging a cord around. This tool-only powerhouse delivers speed, accuracy, and portability for tough spots and long days on the job.

Key Features & Design

• Powerful 24V Brushless Motor delivers high-speed power with zero ramp-up time.
• Drives up to 3 staples per second for rapid repeated fastening.
• Extended runtime — up to 5,000 staples on a single charge with a 2.5Ah lithium-ion battery.
• Depth control via Power Adjustment Dial to set the ideal stapling depth.
• Visibility — Dual LED worklights illuminate dark work areas.
• Firing modes — toggle between bump and sequential firing, with a staple indicator for remaining capacity.
• Dry-fire lockout prevents blank firing and protects your work when the magazine runs dry.
• Compact & lightweight — conquers tight spaces and reduces fatigue (2.76 lb; 7.07" L × 2.91" W × 7.52" H).
• 3/8" crown fasteners supported, with length range 1/4"–9/16".
• Magazine — hollowed-out magazine with bottom loading and a max capacity of 89.
• Belt clip — removable on either side with a lead-in profile for quick access.
• FLEX Advantage — 20% more power, 25% longer runtime, and up to 50% faster charging.
• Cross-compatibility — works with all FLEX 24V batteries, chargers, and tools.

Specifications

• Voltage: 24 V
• Motor Type: Brushless
• Nailer Type: 3/8" Crown Stapler
• Driving Mechanism: Mechanical Spring
• Fastener Crown Size: 3/8"
• Fastener Length: 1/4" - 9/16"
• Fastener Angle: 0°
• Operation Mode: Bump / Sequential
• Max Firing Speed: 3 fasteners per second
• Runtime: Up to 5,000 staples per charge
• Magazine Type: Hollowed-out
• Loading Style: Bottom Loading
• Max Magazine Capacity: 89
• Magazine Angle: 0°
• Magazine Material: Metal
• Tool Weight: 2.76 lbs
• Tool Length: 7.07 in
• Tool Width: 2.91 in
• Tool Height: 7.52 in

Warranty

FLEX Limited Lifetime Warranty - Register your new FLEX tool, battery, or charger within 30 days of purchase at registermyFLEX.com through December 31, 2024 to receive a limited lifetime warranty.

Powered by FLEX 24V technology, this cordless stapler delivers the blend of battery power, runtime, and fast charging that keeps work moving. If you’re installing Tyvek wrap, carpeting, or other fabric-fastening tasks, the FX4521-Z helps you finish faster with less fatigue and more confidence.