The Airflo Depthfinder flylines have gained a reputation as the fastest sinking line of its type on the market.The unique polyurethane coating is capable of holding high loads of tungsten sinking powder, giving denser, slimmer coatings capable of cutting through the water with ease. This lower diameter for a given grain rate, reduces the effects of tidal rips and subsurface currents that slow the sink rate of many sinking lines. Depthfinders have a solid monofilament core and are suitable for fresh and salt water.

Specifications
Manufacturer	AirFlo
Type	Shooting head system with an intermediate running section.
Length	30' head, 75' running,
Line Weight	DF-400 I, 400 grain, ATFM range 8-11 wt rods
Color	Black tip section, peach running line
Core Material	Monofilament core
Sink Rate	Fast sink 8.5"/second sink rate
Surface Coating/ Slickness	Yes

On the Water: I set up the on the water testing to cast the line with two comprable quality rods, at AFTM ratings of 9 and 10. I loaded the AirFlo DF-400-I plus on my Lamson LP4 reel and mounted the reel to the 9’ 9 wt med-fast rod. The line handled quite well allowing effortless casts of 80 plus feet into a light wind and 90' with the wind at my back. The line loaded the rod with just two strokes; this is a very important feature when casting to feeding fish that are 60 plus feet out. Next, I mounted the reel on the 10 wt med. fast rod and repeated the casting tests. I found the line to perform somewhat better with the 10 wt, especially when casting into the wind. My distance increased about 10' on average. As with the 9 wt, the rod easily loaded in two strokes. For me, aside from good distance, is a fly line that comes off the boat deck free of tangles. No other fly line characteristic is more important than tangle free casting. I have missed more quality hook-up opportunities because of this. Admittedly, this characteristic appears to be the most difficult property for the fly line designers to solve. The more line you have laying on the deck, the higher the wind speed, the more likely tangles will happen. Surprisinly, the DF-400-I appeared to perform better than other shooting head systems I have used. However, I need to use the line for several weeks and in more conditions to be reasonably confident that this line is in fact somewhat better. As you can see from the photo below, I was able to shoot the line out and with the fast sink charateristic, hook-up a very nice surf hiding striper! AirFlo Depthfinder DF-400-I Construction-Quality The AirFlo Depthfinder DF-400-I comes from the factory as integrated one piece flyline for overall better strength and smoothness. 4.7 Performance The slick smooth surface coating and quick loading characteristics made for long casts with fewer tangles than expected. 4.8 Price At retail, $67.99 4.5 Application The DF-400-I is well designed shooting head system for both cold and warm water angling scenarios, excellent distance, fast sink in turbulent water and "maybe fewer tangles". 4.8 Score:1-5(5=highest) Total Score 4.7 Plus Minus One piece construction Quality All-around performance Conclusion: The DF-400-I flyline is as advertised, a fly line that delivers long casts,very fast sink, quick rod loading characteristics and quality of construction. Another quality product from AirFlo.