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SI Defense, Inc.
Your source for quality components

SI Defense was conceived by an aerospace manufacturer, which is owned by a Service Disabled Vietnam Veteran located in beautiful Kalispell Montana.

The owner, Richard Sonju, fought for the United States of America in the Vietnam War, where he gathered military intelligence in coordination with the Special Forces on the turbulent borders of Cambodia and Laos.

His first hand experience in the field, along with his history in aerospace manufacturing brings a whole new meaning to reliability and quality in the defense business.


Dick Sonju- Service disabled Vietnam veteran served in U.S. Army, 1968-1969, Ben Het - Dak To

SI Defense employs many veterans and individuals who are passionate about what they do. When a company and its employees are passionate about something, it shows in the products that are offered to its customers. SI Defense uses some of the most sophisticated equipment in the world to build its components, but we still use good old fashion customer service to take orders and answer questions.

SI Defense guarantees the products we offer, and we love to hear from our customers. We want to know how to improve our products; we want to hear your success stories. Our number one priority is to have you as our customer for life!



Contact Information:


The fastest way to reach us is via e-mail as it is extremely difficult to all answer questions on the telephone because of call volume, information, etc. We prefer NOT take orders via telephone simply because details are better conveyed when written. We answer all emails within a very short period of time.


Have a question about an order?
406-752-4253

Contact customer service at adyn@sonjuind.com

Have a sales question?
406-752-4253
Contact sales at sales@si-defense.com

Have a warranty claim or return?
406-752-4253
Contact adyn@sonjuind.com


Return Product Address:


SI Defense, Inc.
ATTN: Returns
2902 Highway 93 North
Kalispell, Montana 59901


SI Defense, Inc. Product Warranty
Return Product Address:


SI Defense, Inc.
ATTN: Warranty
2902 Highway 93 North
Kalispell, Montana 59901


Please contact customer service for more information on returning an item. Thank you.

Refund/Return Policy:

Original sales receipt must accompany returns.

 We accept returns for exchange or refund 7 calendar days after delivery of the product. At our sole discretion after 7 calendar days, we will offer an exchange or store credit only. Items must be in "new, unaltered and unused condition". Definition of new, unaltered and unused condition is:

  • -without showing signs of wear or damage in any way
  • -within 7 calendar days of the delivery date (after 7 days no returns are allowed)
  • -must not be a special order or a custom order
  • -unless noted that it cannot be returned or has a different return  policy time period other than that 7 days noted in that item's  particular item description.


If an item is received damaged or is incorrectly shipped by us please contact Customer Support immediately. Items that are defective and shipped from us or items that you did not order but received from us will qualify for store credit or a cash refund.

Refunds are contingent upon inspection of item(s) once we receive it.

There is a 25% restocking fee for returned items that are not being exchanged and are not damaged. Again you MUST contact us within 7 days if you intend to return ANY item back to our store. Items returned to us AFTER 7 days and WITHOUT contacting us will NOT be refunded.

Customer is responsible for all shipping costs if seller is not at fault.


Contact Information:


Return and Warranty Address:

SI Defense, Inc.

2902 Highway 93 North

Kalispell, Montana


Business Hours:

Monday through Friday

8 a.m. to 5 p.m. Mountain Standard Time



Phone and Fax Numbers:

Phone- (406) 752-4253

Fax- (406) 755-1302