Green’s Dictionary of Slang

1. (UK Und.) burglary tools.

1889

Clarkson & Richardson Police! 315: The spy does not forget to take particulars of the interior of the house, and he is able to report to his pals what will be required in the shape of ‘tackling,’ whether long or short. ‘Long tackling’ means a ‘stick’ and a ‘betty,’ or, in plain words, a small crowbar with a wooden handle.

2. see tackle n.¹ (1)