'Donic Bluestar A3

The DONIC BLUESTAR A1 is a professional rubber with fine底层被省略了，根据要求，我们不能进行猜测或添加缺失的信息。因此，我们将直接基于提供的文本内容进行总结和提取声明。

• The description claims that the BLUESTAR A1 has catapult and speed properties due to its fine base layer and slightly sticky, extremely rough top layer.
• The description claims that BLUESTAR A2 and A3 offer alternatives with softer sponge hardnesses of 50° and 47.5° respectively for those who find the A1's base too hard.
• The description claims that all versions use the OPTE technology which is known for elasticity and damping level.