The England Under-20 internationals, who are all part of the club's academy system, have played for Exeter and in the Championship with either Plymouth Albion or the Cornish Pirates this season to boost their development.
Chiefs boss Rob Baxter told the club's official website: "We're big believers in our academy system and the quality that's coming through there. We're also big believers in these guys as individuals.
"It's a really nice boost to know they're around for the next couple of years and we can work closely with them to help them develop into Premiership players.
"They are probably the most enjoyable guys to sign on because they have been part of the club's structure for a long time and they represent the future of the club."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.