Few teams have the type of success with undrafted free agents like the Los Angeles Chargers.

In fact, at least one has made the final 53-man roster for 21 straight years, which is the longest active streak in the NFL. The past three years have seen four make the 53-man roster out of training camp.

With the 2018 NFL Draft officially in the books, the Bolts have agreed to terms with the following 21 college free agents:

CB Tony Brown — Alabama

A physical cornerback who is a thorn in the side of wideouts, Brown is also a speedster who ran a 4.35 40-yard dash at the Combine. He played in all 14 games a year ago mainly in the slot, tallying 31 tackles, two passes defensed and one pick.

CB B.J. Clay — Georgia State

The 6-0, 190-pound Clay appeared in 46 games with the Panthers, recording 39 tackles, 12 passes defensed and three picks. His top season came in 2016 when he tied for the team lead with three interceptions along with five passes defensed.

T Zachary Crabtree — Oklahoma State

Tasked with protecting QB Mason Rudolph, Crabtree was a first-team All-Big 12 selection in 2017. Overall, the 6-7, 310-pound Crabtree was a steady, reliable rock on the Cowboys offensive line for four seasons.

OT Chris Durant — William & Mary

The 6-4, 310-pound Durant started all four years for the Tribe. Not only that, he was also recognized as third-team All-CAA in each of his final three seasons at William & Mary.

CB Marcus Edmond — Clemson

Edmond was hampered by injuries in 2017, but turned heads in 2016 when given an expanded role in the secondary. The 6-0, 180-pound cornerback posted 19 tackles, three passes defensed and one pick in 323 snaps that year.

CB Brandon Facyson — Virginia Tech

A big corner at 6-2, 203 pounds, Facyson dominated from the second he arrived on campus. He appeared in 55 games with 47 starts over his Hokie career, totaling 131 tackles, five interceptions, 44 passes defensed and three forced fumbles.

G Zack Golditch — Colorado State

The 6-5, 295-pound guard appeared in 43 games with 38 starts over his career at Colorado State. The Rams offense ranked No. 11 in the country during his senior season, in which Golditch was a first-team All-Mountain West selection. He was also part of an offensive line that averaged just one sack allowed-per-game as a junior.

DT Bijhon Jackson — Arkansas

Reliable and sturdy, the 6-1, 339-pound defensive tackle played over 1,000 defensive snaps for the Razorbacks. He started 12 games in his career, notching 47 tackles, nine tackles for loss and 3.5 sacks. He joins Darius Philon as another Chargers defensive lineman to hail from Arkansas.

DE Albert Havili — Eastern Washington

The 6-2, 255-pound Havili was extremely productive over his collegiate career. He registered 199 total tackles, 12 sacks and 18.5 tackles for loss during his time with the Eagles.

LB D'Juan Hines — Houston

The 6-1, 230-pound linebacker led the Cougars and ranked third in the conference with 110 tackles. He also forced three fumbles while adding 6.5 tackles for loss, earning first-team All-American Athletic Conference honors along the way.

TE Cole Hunt — TCU

A hulking 6-7, 255-pound tight end who earned honorable mention All-Big 12 accolades a year ago, Hunt is regarded as a top-tier blocking tight end. He appeared in 27 career games with 17 starts, chipping in as a pass catcher with 12 receptions for 124 yards.

DE Tevin Lawson — Nicolls State

A transfer that played his first three seasons at TCU, the 6-3, 285-pound Lawson flashed in his lone season for Nicholls State. He played in 12 games with seven starts, totaling 25 tackles, one forced fumble and a blocked kick.

TE Ben Johnson — Kansas

Johnson put the cherry on top of an impressive career with the Jayhawks in 2017, catching a career-best 30 passes for 363 yards as a senior. Overall, he played in 45 games with 20 starts, totaling 61 catches for 670 yards.

WR J.J. Jones — West Georgia

Blessed with blazing speed, the 5-10, 173-pound wideout emerged as a big play weapon for the Wolves. Jones had a catch of at least 25 yards in four games a year ago. He's also dangerous on special teams with experience returning punts and kickoffs.

FB Anthony Manzo-Lewis —Albany

The 6-0, 257-pound Manzo-Lewis played a hybrid fullback/tight end role a year ago for the Great Danes. He was a second-team All-CAA selection after catching 20 passes for 188 yards.

RB Detrez Newsome — Western Carolina

The 5-10, 210-pound Newsome can do it all as his 6,969 all-purpose yards is the most in school history. Meanwhile, he ranks second in school history in career rushing yards (3,728), rushing touchdowns (37) and 100-yard rushing games (16). Last year, Newsome became the first Catamount player to ever eclipse 1,000 yards rushing for three straight seasons. A touchdown machine, he's the school's all-time leader with 46 total TDs, adding seven additional scores through the air and two on kickoff returns.

DT Steven Richardson — Minnesota

A stout presence in the middle of the Golden Gophers' defensive line, Richardson started 12 games as a senior, tallying 23 tackles and one forced fumble. The 6-0, 292-pounder finished his impressive career with 103 tackles, 28.5 tackles for loss, 12.5 sacks and five forced fumbles in 48 games.

QB Nic Shimonek — Texas Tech

One of the most accurate quarterbacks in the country, the 6-3, 225-pound Red Raider completed 328-of-493 passes (66.5 percent) for 3,963 yards and 33 touchdowns. His favorite target was wideout Dylan Cantrell, who the Bolts selected in the sixth round.

G Trenton Scott — Grambling State

The 6-5 tackle allowed only three sacks throughout his entire collegiate career. He's fresh off a dominating campaign in which he had 39 pancake blocks without allowing a single sack.

WR Kent Shelby — McNeese State

A tall target at 6-3, 208-pounds, Shelby ranks eighth in school history in touchdown receptions (11), 17th in career receptions (80) and 18th in career receiving yards (1,285). Shelby dominated the competition in 2017, hauling in 48 passes for 625 yards and three TDs.

P Shane Tripucka — Texas A&M