The Wago 222 was very good and has been improved with the 221 again: - Significantly more compact - the difference you realize very clearly in the doses - Transparent for easy control of the clamping - Opening specifically for test probes (one must no longer ran from the cable side with uncertain contact with the head, but can directly from the back through a hole at the contact - super! - Safe clamping even with fine stranded wires, also in combination with rigid thick lines in the adjacent terminal (but not the same!) - Max. 4mm²
The Wago 221 actually has only one disadvantage compared to the 222 - it will only wires clamped securely from 0,14mm². The Wago 222 from 0,08. But this is rarely a problem.