I have a new boxed whole house canister water filter system kit, which includes the mounting bracket, filter change wrench and your first filter. Watts model # OFTWH-C, which is their OneFlow Anti-Scale System For Tankless Water Heaters for up to 5 gpm (18.92 lpm)
Similar kits sold by several manufacturers are often called, "big blue" whole house systems.
This particular Watts system is designed to provide scale prevention and protection, in addition to filtering out more standard things like sediment, rust, etc. This system can use several different types of filters, not just the more expensive type of filter included with this Watts system.
No damage or anything. Very clean box, no box damage either. I have some access to some plumbing supplies from time to time and sell the items I don't need to keep on hand for backup inventory.
$80 FIRM. This particular version sells online for over $200. You can find it listed on sites such as Home Depot or plumbing wholesale websites.
Replacement filters are sized approximately 4.5 inches wide x 9.75 inches. This is a standard size so it will be easy to find replacements.
This is an ideal product to purchase on Craigslist because unlike electronics, there's nothing that can go wrong or malfunction. It's just a screw-on cap with canister, a filter and a wrench.
See below for more product details:
Features
Chemical free treatment for scale prevention and protection
Virtually maintenance free environmental-friendly technology
Requires no control valve, chemical additives or electricity
Improves equipment efficiency
Flow rate up to 5 gpm
This OneFlow® anti-scale system, model OFTWH-C, conditions cold tap water and provides scale protection on internal plumbing surfaces to extend the life of equipment by transforming dissolved hardness minerals into harmless, inactive microscopic particles. Used for single residential tankless water heater unit, the specially designed components are installed before a water using device (water heater) to protect against the effects of hard water. The OneFlow anti-scale system is not a water softener and does not add chemicals or remove minerals, but provides environmentally friendly technology to prevent scale buildup.
The OFTWH-C system consists of a single blue housing, 14 inches tall with a 3/4 inch FNPT connection and OneFlow media cartridge that should be replaced once every 2 years. Nominal flow rate up to 5 gpm (18.92 lpm).