5.0 (1 review) Beta

CompX National Pin Tumbler Mailbox Lock

Sku: C9100 / C9200
Pin Tumbler Mailbox Lock main image CompX National C9100 / C9200 Mailbox Lock - Gallery Image CompX National C7120 Heavy Duty Hook Cam - Gallery Image
Pin Tumbler Mailbox Lock main image
Select Mailbox Locks:
Pin Tumbler Mailbox Lock - Clockwise Operation Details
Pin Tumbler Mailbox Lock - Clockwise Operation. NOTE: Extra keys may only be purchased with the purchase of a new lock.

Price: $22.27

96 in Stock. More on the way! Arriving by 06/22/2026.
Bulk Pricing
2 units $20.27 ea
5 units $18.27 ea
10 units $16.27 ea

SKU: C9100

Free shipping not eligible Shipping charges will apply to this item.

Extra Keys $7.17 each

To add extra keys, C9100 must be in the cart.

SKU: C9100 / C9200
Product Description
The CompX National C9100 / C9200 Mailbox Lock is a dependable replacement for worn or damaged National-brand mailbox locks. Designed as a direct replacement, this durable cam lock is commonly used in residential and centralized mailboxes.

This lock matches the USPS L-1172C form factor, making it a suitable replacement option for mailboxes originally equipped with USPS-style locks. Ideal for restoring secure mail access, the CompX C9100/C9200 mailbox lock offers smooth operation and long-lasting performance.

Please compare your existing lock’s dimensions, cam style, and rotation to ensure proper fit.

  • APPLICATION – Replaces USPS-L-1172C locks. Exterior pedestal-mounted neighborhood boxes. Has keyway dust shutter for lock protection. Clip mounted. C9100 & C9200 are the only mailbox locks approved by USPS for 4C (CBU) mailboxes. 
  • OPERATION – C9100 operates clockwise to unlock. C9200 operates counter clockwise to unlock. Key removable in locked position only.
  • KEYING – Available keyed differently only (2,000 changes).
  • PACKAGING – Includes: a spring clip, mounting nut and (3) keys.

Looking for Keys to Your Mailbox?
1000PS - 1999PS
2000PS - 2999PS
3000PS - 3999PS
4000PS - 4999PS

Heavy duty hook cam can be ordered below - click on thumbnail at left to see a larger image.

C9100 Instruction Sheet
C9200 Instruction Sheet
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View more details
Bulk Pricing
2 units $12.07 ea
5 units $11.07 ea
10 units $10.07 ea
20 in stock
$13.07
Free shipping not eligible Shipping charges will apply to this item.
CompX National C9100-C9200-EXTRA-KEY
Extra Cut Keys for C9100 & C9200 Mailbox Lock Packages - CompX National D4301 Key Blank
Duplicate Keys for C9100 & C9200 Mailbox Lock Packages.
795 in stock
$7.17
Free shipping eligible Ships free when your cart contains only free-shipping items and totals $35+.

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Product reviews
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Customer feedback
Showing 1 of 1 reviews
5.0
★★★★★
★★★★★
Great fit
The key fit perfectly and arrived quickly
SKU: C9100
Sandra
Apr 22, 2026