Simba's DD Press Rings set the standard for pressing efficiency and remain unique both in their design (which is patented) and their performance.

The rings have a self-sharpening cutting edge mounted on a broad, carefully angled shoulder. This enables them to cut clods effectively, crushing the parted halves so they disintegrate, while also contacting over 80% of the soil surface so they consolidate and level the seedbed, leaving a ridged, weather-proof surface.

As a result they do not lose their efficancy as cast rings do. In addition, the DD has no spokes so is not so prone to blockages caused by stones kicking up and getting stuck between spokes and pillars etc. Its broad shoulder enables it to run on top of lighter soils and consolidate them, rather than sinking into them as cast rings tend to do.