BPC Stainless Steel Cavity Wall Ties Type 4 – 225mm (Cavity Width 76-100mm) – Box of 250 Ties HT4 light duty housing wall ties are suitable for dwellings up to 10m high and are tested as Type A (sound) and Type 4 (strength) to BS EN 845-1. Designed to secure two leaves of masonry together, with double drip feature to prevent moisture travelling across the tie. Type: 4 Overall Length: 225mm Cavity Width: 76-100mm Material: 304 Grade Stainless Steel Pack Qty: 250