Graver's QSL cartridge is available in just one size: 0.5 microns. That's because it's designed to do just one thing: protect your 0.45 micron final membrane filter.

QSL is a dual-layer cartridge, so it gives you two filters in one cartridge at a great price. The outer layer is a nominally-rated polypropylene pre-filter. The inner layer is an absolute-rated (99.98% efficient) 0.5 micron PES membrane. Together, the two layers help protect the downstream 0.45 micron final filter from prematurely clogging.

If you're using Graver's ZTEC WB 0.45µ cartridge—or any 0.45µ PES membrane cartridge—for your final filter, you need QSL to help guard it, and maximize your filter's on-stream life.

• Serial layered design — enhances capacity and simplifies prefiltration requirements
• Absolute rated (99.98%) at 0.5 micron — acts as an ideal prefilter for 0.2 micron and 0.45 micron membrane filters
• Fixed pore construction — resists dirt unloading at maximum differential pressure
• Silicone O-Rings (Custom o-ring material available. Contact us for availability)
• P7 Ends