WRS Caldwell Series 150 Spirex Heavy Duty Spiral Balance for Non-Tilt/Sideload Windows – 5/8", 37" Length, Black Tip (30–40 lbs) – Durable Heavy-Duty Steel Tube for Smooth Residential & Commercial Non-Tilt Window Operation

23.49

Upgrade heavy-duty window performance with the WRS Caldwell Series 150 Spirex Heavy Duty Spiral Balance, purpose-built for non-tilt and sideload window applications. Crafted with a reinforced 5/8" steel tube and precision-calibrated spiral rod, this balance delivers consistent lift support for sashes weighing 30–40 lbs. Each unit is AAMA Class 2 verified, providing a minimum of 40% lift assistance for safe, reliable, and long-lasting operation.

The Series 150 Spirex line provides a universal black tip design across all lengths, making selection straightforward:

• Lengths available from 17" to 61"
  
  
• Standard 5/8" tube diameter (compatible with some 9/16" applications)
  
  
• Black tip coupling calibrated for 30–40 lb sash weights
  
  
• Sold individually; recommend replacing in pairs for best results
  
  

Selection Guide:

1. Measure only the metal tube length (do not include spiral or tip).
   
   
2. Confirm tube diameter (5/8" is most common; 5/8" and 9/16" often interchangeable).
   
   
3. All 150 Series balances use a black tip, calibrated for 30–40 lbs per sash.
   
   

Please note: balances 15" or longer cannot be shipped to P.O. boxes via USPS. UPS does not deliver to P.O. boxes.

With straightforward DIY-friendly installation, Series 150 balances are ideal for homeowners, contractors, schools, and property managers who need a cost-effective alternative to full window replacement.

For over three decades, WRS Window Repair Systems has been the trusted source for durable, high-quality window hardware. Choose the Caldwell Series 150 Spirex Heavy Duty Spiral Balance for lasting performance, safety, and reliability.