The PI model I have for sale is rated for 100' depth. The pulse delay on this machine is set at 15Us, which as stevemc noted, makes it hot on small gold. It is a very good beach and diving machine.
I am selling mine for $575 OBO. It still has some warranty left.
Headphone Transducers: Permanently encapsulated high-output piezoelectric.
Audio Frequency: Adjustable
Headphone Earcups: Heavy-duty polymer full ear surround; extra comfortable soft cushions, ambient noise blocking up to 24 decibels, heavy-duty ear-to-ear wiring with new seals for added strength; heavier duty sealing plates; UW connector for interchangeable searchcoils.
Headphone Frame: Adjustable padded headband, no screws, no wire frame, no rust, compact carry foldable design.
Controls: Full-range Volume, Frequency Adjust, & Tuning
Search Mode: Slow motion all-metal
Operating environments: Salt & fresh water to 100 feet, beach, & rain storms.
Cable: Straight, heavy-duty coil wire for added strength.
Hand Grip: Soft foam anatomic for all-day use.
Rods: Self-draining anodized aluminum with durable baked on black powder coating; lower shaft extension for easy conversion to wading configuration.
Armrest: Adjustable stainless steel with waterproof padding
Isolator: Heavy-duty non-metallic with nylon wingnut & stud assembly.
Rod Length: 27 to 53 inches.
Breakdown: Three pieces for easy storage and travel.
Weight With Batteries: 3.5 pounds.
Batteries: (2) 9-Volt cells of any type, carbon-zinc, alkaline or rechargeable.
Battery Life: 8-12 hours (alkaline)
Applications: Jewelry, relic, and coin hunting.
Warranty: Two Years
NOTE: Specifications and features subject to change without notice