All AustriAlpin Steel Carabiners are cold forged and milled to achieve the highest degree of precision, strength and consistent quality. Casting (as used by many low cost and most asian brands) is a grossly inferior production technique resulting in poor wear, inconsistent strength, and potential fracturing. It's a bold statement about our carabiners but there are simply no safer PPE products on the market.. Carabiners come in four characteristic shapes: Oval: Symmetric. Most basic and utilitarian. Smooth regular curves are gentle on equipment and allow easy repositioning of loads. Their greatest disadvantage is that a load is shared equally on both the strong solid spine and the weaker gated axis. D: Asymmetric shape transfers the majority of their load onto the spine, the carabiner's strongest axis. Offset-D: Variant of a D with a greater asymmetry, allowing for a wider gate opening. Pear/HMS: Specialized oversized offset-D's used in belaying. These are usually the heaviest carabiners.