John Guest Speedfit Low Fit 20mm Castellated Panels are designed to provide a high output, low height, screeded underfloor system. The 20mm panel has equally spaced castellations at 50mm to allow 15mm pipe to be clipped in securely and accurately as per design specifications Installation of the panels is fast and simple as it features an overlapping alignment system for simple hassle-free panel laying, as well as a super strong adhesive backing. This allows for the panel to be installed directly onto the existing sub floor structure. The open grid design ensures the screed layer poured on top flows smoothly and evenly over the panel.