From the article above...
“The two bombs that killed three people and injured at least 176 at the Boston Marathon on Monday were made from six-liter pressure cookers packed with shards of metal, nails and ball bearings and stashed in black duffel bags, police sources revealed today.
The deadly devices ... have previously been used in terror attacks in Afghanistan and Pakistan and were also used in the foiled Al-Qaeda attack on Times Square in 2010.