NASCAR penalized four Craftsman Truck Series teams on Thursday morning, all for the same violation from the past two race weekends at Darlington Raceway and Kansas Speedway.

Each of the four teams was discovered to have violated NASCAR Rule Book Sections 14.2.3.3.1 B&C: Driver’s Window Net, a safety penalty.

A driver’s window net must meet the SFI 27.1 specification and display a valid SFI 27.1 label. This SFI specification means that the window net has been tested to meet the minimum standards for safety.

Additionally, window nets must not be used beyond two years from the date it was manufactured.

For the Darlington infractions, the Nos. 46 and 47 Toyotas of G2G Racing, driven by Brennan Poole (36th) and Dawson Cram (35th), respectively, were found to have violated the rule book. Crew chiefs Timothy Silva (No. 46) and Daniel Killius (No. 47) were each fined $5,000 and each team has been assessed with the loss of 25 points.

MORE: Eckes wins at Darlington | Full race results

For Kansas, the Nos. 12 and 20 Young’s Motorsports Chevrolets of Spencer Boyd (26th) and Nick Leitz (21st), respectively, were hit with the infraction penalties. As a result, crew chiefs Bradley Means (No. 12) and Joseph Lax (No. 20) were each fined $5,000 and both teams incurred a 25-point penalty.

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The series next races on Saturday at North Wilkesboro Speedway in the Tyson 250 (1:30 p.m. ET, FOX, MRN, Sirius XM NASCAR).