It's probably the best top cap you will ever have. One piece, bolt-top cap with allen 5mm socket.
Not suitable for "expanding" star nuts with the steel spring (used in carbon steerer), unless you want to mount it without the spring. But it is compatible with ENVE Compression Plug (recommended for carbon steerers).
Size (Mass +/-1g): only 4g$31.37 (RRP)$31.37 (RRP)$31.37 (RRP)$31.37 (RRP)