Campagnolo requires use of their UT-CN300 Chain Tool for 11-12speed chain installations, which is not only used to break chains properly but also to drive and peen the pin precisely. Use of other tools could damage the chain and/or result in chain failure.
The Campagnolo UT-CN300 chain tool keeps the chain perfectly stabilized, allowing you to install the Ultra Link connector with the exacting precision the design demands. The UT-CN300 Chain Tool has a specially designed, ultra precise, tapered tip end the driving pin on the tool. The pusher of the UT-CN300 is provided with a replaceable tapered tip pin. If the pin becomes worn, you will need to replace it with Campagnolo spare pin UT-CN301.
This exacting process becomes even more crucial with flush pin design of the 5.15mm 12 speed chain. The Campagnolo 12-Speed chain will come with highly specific instructions that are also available on the Campagnolo website. If you do not have the correct tool and informed experience, take your bike and chain/pin to your nearest Campagnolo Service Center or trusted mechanic for installation.
Campagnolo part: UT-CN300