The T-H3S-OS-NG from Takagi is an Outdoor Tankless Water Heater, Natural Gas, 180K BTU. 

Features:

• Continuous Maximum Flow Rates Up to 10.0 GPM;

Durable Heat Exchanger:

• Primary Heat Exchanger is constructed of HRS35 Commercial-Grade Copper
• Secondary Heat Exchanger is made of Type 316L Stainless Steel
• Energy Star Qualified;

Safety:

• Air-Fuel Ratio (AFR) Sensor
• Exhaust & Water Temperature Safety Control
• Overheat Cut-Off Fuse
• Electronic Ignition - No Pilot Light;
• Internal Freeze-Protection System;
• Includes a Wall Mount Temperature Remote Controller and Advanced Diagnostic to Simplify Troubleshooting;
• Complies With Lead Free Standards;
• Internal Freeze Protection System;

Power Direct Vent Design:

• Exhaust, 3" PVC Venting up to 70 Feet or 4" PVC Venting up to 100 Feet
• Provides flexible venting with PVC, CPVC, or ABS Pipe for Intake and Exhaust (solid core only). Canadian Installations Require ULCS636 Listed PVC or CPVC Pipe for Venting.
• Category IV Stainless Steel venting can also be used
• Ultra-Low NOx Condensing Technology.

Technical Specifications:

• NG Input Min. 15,000BTU/h Max. 180,000BTU/h;
• Water Pressure Min. 15psi Max. 150psi;
• T-H3OS Manifold Pressure Natural: 2.1"WC Propane: 2.55"WC;
• Gas Connection 3/4" NPT;
• Water Connection 3/4" NPT;
• NG Gas Pressure Inlet Min. 5.0"WC Max. 10.5"WC;
• Weight 58lbs;
• Dimensions 22.4" x 17.7" x 10.7";
• Ignition Electronic Ignition;
• Electrical Supply AC 120V (60 Hz).