23_3/4x23_3/4x1Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack Reflectors & Grow Lights The HI12943 is a pH

The HI12943 is a pH electrode for the direct measurement of pH in soil and soilless media

100% green technology

- Blink in 1 Second: Under or Over Voltage Protection

Apply early morning or evening to avoid UV damage

Effective against spider mites

23_3/4x23_3/4x1Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack Reflectors & Grow Lights The HI12943 is a pHNordic Pure Custom MERV 12 Plus Carbon air filters are made based on the actual measurements so be sure to measure your current filter to get the EXACT dimensions before ordering. As with all Nordic Pure filters, the effective life of your filter depends on the environment in which you live. We recommend changing 1 and 2 filters every 30 90 days. Our 4, 5 and 6 inch thick filters could last up to 6 months. EXACT MEASUREMENT: Furnace and air condition