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Description
Flowmonster Performance Muffler 3 in Dual inlet & outlet 12599-FM 409 StainlessOverview The Flowmonster series of absorption style mufflers deliver a moderate tone for the enthusiast looking for a deeper, more aggressive exhaust note than most OE (Original Equipment) mufflers, unlike the racey exhaust note associated with "chambered" style mufflers. Interior construction features 3. 50 inch "straight through" perforated 409 stainless steel tube surrounded by high temperature sound absorption packing material which helps to
Overview
The Flowmonster series of absorption style mufflers deliver a moderate tone for the enthusiast looking for a deeper, more aggressive exhaust note than most OE (Original Equipment) mufflers, unlike the racey exhaust note associated with "chambered" style mufflers.
Interior construction features 3.50 inch "straight-through" perforated 409 stainless steel tube surrounded by high-temperature sound absorption packing material which helps to deliver a deeper, mellower exhaust note. The internal design is reversible allowing the flexibility to be installed in either direction to best accommodate fitment with the intended vehicle. The fully MIG-welded 409 Stainless Steel material is embossed with the "FLOWMONSTER" logo on the case.
Interior construction features 3.50 inch "straight-through" perforated 409 stainless steel tube surrounded by high-temperature sound absorption packing material which helps to deliver a deeper, mellower exhaust note. The internal design is reversible allowing the flexibility to be installed in either direction to best accommodate fitment with the intended vehicle. The fully MIG-welded 409 Stainless Steel material is embossed with the "FLOWMONSTER" logo on the case.
Features:
- 409 Stainless Steel construction for superior corrosion resistance and good looks
- Interior construction features high-temp interior sound absorption material delivering a deeper, mellow exhaust tone
- Perforated High-Flow straight-through tube design for increased exhaust flow
- Moderate increase in interior tone over most OE mufflers
- A stainless steel performance muffler at an economical price
- Internal Design is reversible allowing flexibility to be installed in either direction
- Sold Individually
- This is a Universal Fit muffler - Not a Direct fit. Some adaption may be required for proper fitment on some applications
| Body Height (in) | 5 |
| Body Length (in) | 22 |
| Body Width (in) | 11 |
| Finish | Natural |
| Fitment | Universal |
| Inlet Connection Type | Pipe Connection |
| Inlet Inner Diameter (in) | 3 |
| Inlet Outer Diameter (in) | 3.13 |
| Inlet Position | Dual |
| Material | 409 Stainless Steel |
| Muffler Series | Flowmonster |
| Muffler Type | Absorption / Glasspack |
| Outlet Connection Type | Pipe Connection |
| Outlet Inner Diameter (in) | 3 |
| Outlet Outer Diameter (in) | 3.13 |
| Outlet Position | Dual |
| Overall Length (in) | 28 |
| Reversible | Yes |
| Shape | Oval |
| Sound Level | Moderate Sound |
| Type of Muffler | Absorption |
| Part Number | 12599-FM |
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.5 ★★★★★
Based on 9 reviews
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Product Reviews
★★★★★ 5
Tastes Like Banana Pudding and Dunkin Banana Flavor!
Flavor Name: Banana Bread, Size: 25.4 Fl Oz (Pack of 1)
I don't know why someone would buy this expecting it to taste like real bananas like come on ppl lol. The only way to attain a syrup that tastes like real banana bread is to make it at home. This is an artificially flavored syrup so obviously it tastes that way! I have made banana bread syrup (more like a sauce) at home and it is delicious, highly recommend!! But this is way more shelf stable and tastes amazing in an iced latte as well! Different than home made but still good. To me this tastes like banana pudding mix which also has a fake banana taste. It also tastes EXACTLY like the new Dunkin banana flavored syrup which is what I was looking for! I use 1.5 tbsp syrup, a little vanilla paste, 2 espresso shots and 2 percent milk with plenty of ice. I like keeping my latte calories below 200 and not super sweet tho so you can up it to 2 tbsp. The cals in this are not terrible, 70 cals for 2 tablespoons. Usually my syrups have 50-60 cals for only 1 tbsp so I'm pleasantly surprised this is a little lower. I bought a second bottle because I'm afraid this is a limited release lol.
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Reviewed in the United States on April 1, 2026
★★★★★ 5
Delicious
Flavor Name: Coconut, Size: 25.4 Fl Oz (Pack of 1)
Delicious coconut syrup. This has upgraded my morning coffee beyond words. Better than store bought lattes. Great price point. My summer go to coffee upgrade
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Reviewed in the United States on June 7, 2026
★★★★★ 5
Excellent product!
Flavor Name: Raspberry, Size: 25.4 Fl Oz (Pack of 1)
This is a great product! The quality, taste and smell are outstanding. Mixes great every time and the syrup dispensers fit perfectly. Highly recommend this product.
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Reviewed in the United States on June 8, 2026
★★★★★ 4
Worth it!
Flavor Name: Coconut, Size: 25.4 Fl Oz (Pack of 1)
Compared to Torani syrups I prefer this one for my coffee in the morning. It’s soft, smoother and tastes delicious combined with cream. You get a lot for the price you pay and it lasts.
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Reviewed in the United States on May 26, 2026
★★★★★ 5
Enjoy it
Flavor Name: Blonde, Size: 3.5 Ounce (Pack of 2)
Great value as the price is better that the supermarket. Easy to make and the quality is wonderful. I like to make iced lattes with this espresso powder and it is so easy to do so.
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Reviewed in the United States on October 7, 2025