These bulbs work with Cougar factory spec turn signal flashers, but they may not work with all aftermarket flashers, especially if they claim to 'exceed' the factory specs. Because of this, you may want to order our turn signal flasher that was specifically designed to work with the Plasma LED bulbs: 
Part #:12827

As seen on Gearz with Stacey David - After searching far and wide, to and fro, here and there...we finally found the best LED replacement bulb for any car that uses 1157 taillight bulbs. These new "Plasma" LED bulbs are significantly brighter and more efficient than your standard bulbs, and shine a true red, for a rich color. This is a 2-pack of bulbs to replace the taillights in a wide range of vehicles. We also sell them in 6-packs for Cougar, Shelby, and Thunderbird, as well as 20 packs for those with a larger fleet.

We're also told that these will work as replacements for 2057, 2357, 2397, and 7528 bulbs, but haven't tested ourselves to verify. Let us know if you find out!

1967-68 Cougar owners: you're lucky; these will work in your car with no modifications. As you seen in the video, they work fine right out of the package whether you have the new and improved solid state sequential unit or the original mechanical unit.

1969-73 Cougar owners: you will need additional equipment in order for these bulbs to function correctly with the sequential turn signals. See the chart at the bottom of this page for which components you'll need to have a fully functioning LED light system.

Applications: Stop lamps / Rear turn signals / Parking lights

Specifics and Benefits:

• 8W Dual / Double Contact Point Plasma & CREE LED Auto Tail Brake Light Bulb
• Better efficiency than stock bulbs, headlights do not dim when applying brakes
• Direct Plug-In Replacement; No socket alterations required
• Brightness: 90 lumens (low), 200 lumens (high)
• Current draw: 80ma (low), 300ma (high)
• Life expectancy: up to 30,000 Hours
• Completely fills the taillight reflector, illuminates red, not warm white like incandescent

Overall Dimensions:

• 2" (Length - Tip to Socket Bottom) X 0.75" (Diameter)
• 1 3/8" extends out of the socket

Additional Information:

We should let you know that there is another bulb on the market coming from China and marketed on ebay that looks virtually identical to our bulb. We have tested the competitions' bulb and find that it looks and fits just like ours but the brake light function is noticeably dimmer. There has been some discussion on whether or not one might encounter some attention from law enforcement due to the shockingly bright brake light function of these bulbs. Based on our experience, our conclusion thus far has been that this should not be a concern. Here are some excerpts from NHTSA documents: DOT HS 811 127 and DOT HS 811 329.

"Data suggests that failure to respond (or delay in responding) to a stopped or decelerating lead vehicle is generally a result of distraction, and in particular, improper allocation of visual attention. Thus, VTTI’s approach to the rear-end crash problem has argued that a successful rear signaling system would work to redirect driver visual attention to the forward roadway (for cases involving distracted drivers),"

"Rated discomfort glare is closely related to rated attention-getting. It appears that it is necessary to accept somewhat greater rated discomfort glare to achieve greater attention getting. Here again, the result is the same as for earlier tests with incandescent lamps, which showed a near-identical ordering for discomfort glare and attention-getting for various enhanced rear lighting systems. "

Cougar compatibility chart: Since Cougars have the added fun of sequential turn signals, some cars will need additional components to make the turn signal system work properly with LED taillights. Click the image below to view the full-size version.