If you've come across a used Boss Frog rollbar and installed it in your Miata, the seatbelts sometimes wont retract as well as they did due to binding. These bolt-on adapters help the seat belts slide a bit easier. Installation does require cutting off the OEM belt guides.

These were used on 2005 and earlier Boss Frog and Hard Dog Rollbars. BF started including them after 2005 until BF closed their doors a while back.  We have confirmed fitment up to 1997 (see video). See below note for 98-200X model years.

Price is for the pair (Single piece also available).
 
Assuming that you tilted the seatbelt reel toward the inside of the car and trimmed the plastic bits properly per the Boss Frog instructions, these seatbelt adapters will help improve the belts retraction. Factory level of retraction is a thing of the past though... you've modified your car beyond that ...
 
Original Boss Frog instructions are available for download here: BOSS FROG INSTRUCTIONS
 
 
***NOTE**** 

The original design did NOT intend for the shoulder of the bolt to fit into the hole in the extender.

TEST that your belt tongue will pass through the extenders BEFORE you cut off the OEM guide.

Depending on the year of your car, there may be way more force/pressure needed to get the seat belt toungue through the opening of the extender than the BOSS FROG instructions let on. We have added some clearance to original design of the opening to help. If you cant get the tongue through you can modify the plastic on the tongue by sanding or shaving it down. Do NOT modify the extender for clearance. 

The installation video uses a 91-97 miata seat belt. Other years may require modification to the plastic surround of the seat belt tongue.

If you are not comfortable modifying the plastic around the seat belt latch in your 98-200X DO NOT BUY THESE EXTENDERS. We have not tested them on later years and cannot confirm that they fit. NO RETURNS ACCEPTED for 98 -newer models.

Satin Black is only available with Delayed Production. We will include it with other satin black pieces when we send out for powder coat. Satin Black pieces are NOT kept in inventory.

If you need the extenders "ASAP/next week/I need these for an autocross this weekend".... DO NOT expect them before 2-3 weeks especially with current COVID-19 delays in shipping.

With current (4/22) steel prices, once inventory is depleted, these will be cut per order. If the page shows we're out of stock, choose the Delayed Production option
 
Updated 4/02/22