The certificate Skilled Trades Ontario issues after a candidate passes the certifying exam for a trade.
In Ontario, completing an apprenticeship earns a Certificate of Apprenticeship; passing the certifying exam earns a Certificate of Qualification. Because 313A is a compulsory trade, practising it legally requires a registered training agreement, a provisional certificate or a Certificate of Qualification, according to Skilled Trades Ontario. A C of Q in this trade must be renewed to stay valid.
Source: Skilled Trades Ontario: Refrigeration and Air Conditioning Systems Mechanic