HYDRA'S shackles for Steve
Watching these gifs for the millionth time, it's just heartbreaking to realize HYDRA probably started making them as soon as Steve was picking up active duty.
CA:TWS takes place in 2014, around 1.5-2 years after Steve woke up. He's been with SHIELD all that time, so they've probably been assessing him just like they did with Tony. We know they've been monitoring him through his bugged apartment and the tracker in his stealth suit. Brock Rumlow wasn't surprised when Steve jumped out a plane without a parachute, making it clear he had done similar things before. They know he has skills, strength and durability, they need heavy restraints.
You can't tell me HYDRA bugged his home, tracked his every move, gave him a STRIKE team that was nearly all HYDRA soldiers, crowded around him with cars and helicopters and guns on the street, but didn't immediately start making shackles to fit him when he became active again.
They couldn't just use their regular ones because Steve has a stronger enhanced physiology than the kind they were used to (with the Winter Soldier).
Don't imagine Steve finally feeling at ease with his STRIKE team only to later find out they were just assessing him to figure out what restraints to use when they would take over.