Found a review of the Delta 3 at ZuluSports.com. Here it is:
The Delta III incorporates some of the finer features in regulators at a reasonable price. It has an adjustable airflow deflector, which helps prevent the escape of air in a "free flow," and a variable airflow control dial for fine-tuned breathing.
With the Delta III, airflow adjustment while diving is easy, even with gloves on, and the dual exhaust vents minimize those vision-obscuring air bubbles.
The faceplate-mounted diaphragm purge valve is easy to engage and makes purging and clearing predictable. There's nothing like an unexpected rush of air in your mouth to surprise you underwater.
As tested, our Delta III featured a piston-regulated valve of proven design, called the PX2. It features two high-pressure air ports, and four low-pressure ports, on a swiveling head.
On one dive, I purposely sucked my tank completely dry. Until my last two breaths, breathing was as smooth and easy as with a full tank, thanks to the engineering quality of the piston.
Overall, the Delta III is a smooth and easy breathing regulator. It's also a fairly lightweight unit, which makes it comfortable. The only drawback is that it doesn't always settle down and to the side, making recovery a bit tricky. To make up for that, simply sweep your arm wider and higher.
MSRP: $425.00
Type: First and Second Stage
Inhalation Effort: Diver adjustable 0.0 - 2.5 cu. in. water
Exhalation Effort: 1.1 cu. in. water
Flow Rate: 30+ Standard Cubic Feet/Minute
Material: ABS/Polycarbonate composite
Special Features: Dynamic Adjustment (patented) offers preferred breathing resistance throughout dive; adjustable venturi system; computer optimized deflector vane; diver adjustable inhalation effort; orthodontic mouthpiece
Recommended Ability Levels: Intermediate, Advanced
User: Unisex
Hope this will help
Mike