The Hotdive ST4 Set delivers professional-grade performance with durable stainless steel construction, balanced air delivery, and fine-tuned breathing adjustment — ideal for both recreational and advanced divers.

Hotdive ST4 Regulator Set

• ST4 Matte Silver (S3 1st Stage + T4 2nd Stage + T3 Octo + SPG)
• ST4 Matte Black (S3 1st Stage + T4 2nd Stage + T4 Octo + SPG)
• ST4 Black Rainbow (S3 1st Stage + T4 2nd Stage + T4 Octo + SPG)

Key Features

• Balanced diaphragm 1st stage for consistent airflow at any depth
• Pneumatically balanced adjustable 2nd stage ensures smooth breathing effort (1.2–1.5 CIW)
• Durable materials: Marine-grade SUS316 body & components
• Venturi control and breathing resistance knob for personalized airflow adjustment
• Heat exchanger for improved cold-water performance
• Food-grade silicone mouthpiece with reusable clamp
• Available in DIN connection
• Over-balanced diaphragm design with swivel turret for flexible hose routing

Technical Specifications:

1st Stage (S3)

• Type: Over-balanced diaphragm
• Connector: DIN (300 bar)
• Material: SUS316 stainless steel body & components
• Ports: 2 HP (7/16”) + 5 LP (3/8”)
• Intermediate Pressure: 130–145 PSI (9–10 Bar)
• Weight: DIN 764 g (1.68 lb)
• Hose: 0.75 m LP Flex Hose
• Swivel turret design for smooth hose positioning

2nd Stage (T4)

• Type: Pneumatically balanced, adjustable
• Inhalation effort: 1.2–1.5 CIW
• Material: GF Enhanced PA + SUS316 metal valve
• Mouthpiece: Food-grade TPU with reusable clamp
• Weight: 246 g (0.54 lb) / Octo 189 g (0.42 lb)
• Dive / Pre-dive switch for easy flow control