The largest apparel deal in Connacht Rugby's history is wide ranging and will also deliver playing, training and support staff apparel for the Connacht Eagles' British & Irish Cup squad, age-grade squads, Academy, Women's, Connacht Junior squads and Connacht referees.
"We were enormously impressed by BLK's story and product," said Alex Saul, Connacht's head of commercial & marketing.
"The technology involved with BLK products demonstrates an exciting and innovative company that is cutting edge in its approach.
"BLK's parent company has a proud heritage in rugby in the southern Hemisphere and we are delighted to become their lead team in Europe as they look to establish the brand over here.
"Their significant four-year commitment to Connacht Rugby demonstrates how far the province has come in these past few years."
CEO at BLK, Tyron Brant, said the deal was part of their expansion plans for the global sports brand across Europe.
"At BLK we are committed to providing the most technologically advanced playing apparel on the market, so to be aligned with a major rugby union team like this is a testament to the standard of our apparel.
"We look forward to seeing the men's team take to the field in their BLK gear."
Australian-based BLK has become a major international brand since it was created in 2011. With worldwide distribution, BLK are the official apparel partners of a number of national and international rugby teams such as Manu Samoa, Fiji, Tonga, University of Canberra Brumbies, Melbourne Rebels and Canterbury Rugby Union.
In addition, they boast over 4,000 teams worldwide who exclusively carry BLK team wear.
The Connacht product range has been developed to fulfil the needs of the modern athlete and supporter, from technical training and matchday equipment and apparel to a superior lifestyle and supporters range.
Fans can look forward to the unveiling of the official Connacht home, away and alternative jerseys later this summer.
The Connacht BLK range will be available to purchase through the Connacht Rugby online store and Elverys Stores nationwide.