Allstar Performance ALL34160 12" Auger Style Muffler

I had installed a glass pack on my Dodge Dakota, but it was just too loud. I had previously installed an internal ( in the tailpipe ) spiral muffler. It did a good job of cutting the noise, but it was restrictive and ended up blowing out of the pipe. I bought this even though the information was minimal. The inlet is 4 inches, the outlet is also 4 inches, but the outlet is curved inwards. I had to fabricate a reducer to attach it to my 3 inch pipe. The picture for the item is showing the inlet side.The muffler seems to flow well due to its 4 inch diameter. It seems to cut the mid and high frequencies while leaving the low frequency rumble. While idling, it has a low pitched rumble. While cruising, the cabin sound is minimal. This muffler combined with a glass pack makes my truck sound like it has some serious power under the hood ( I wish ) without being annoying to the neighbors.