Jailbirds in at least 21 cities, including in the Big Apple, will go on strike Tuesday over prison conditions they’re comparing to “modern slavery.”

During the 19-day strike — from Aug. 21 to Sept. 9 — inmates plan to refuse to work, organize sit-ins and in some cases not eat, to draw attention to poor prison conditions and what they say is exploitative labor.

One or more of Brooklyn’s two prisons will be affected, according to USA Today.

Prisoners have outlined 10 national demands that include “immediate improvements” to conditions and for inmates who are forced to work while incarcerated to be paid the “prevailing wage in their state.” They’re also asking that the voting rights of ex-felons should be reinstated and an end to “over-sentencing and parole denials of Black and brown humans.”

“The main leverage that an inmate has is their own body,” Amani Sawari, a spokesperson for the protests, told Vox. “If they choose not to go to work and just sit in the main area or the eating area, and all the prisoners choose to sit there and not go to the kitchen for lunchtime or dinnertime, if they choose not to clean or do the yardwork, this is the leverage that they have. Prisons cannot run without prisoners’ work.”

Prisons in at least 17 states are expected to participate in the demonstration, spearheaded by Jailhouse Lawyers Speak, a network of jailed prisoners rights advocates based out of Lee Correctional Institution in South Carolina and supported by the prisoner-led trade group Incarcerated Workers Organizing Committee, USA Today reported.

The strike is timed to begin on the anniversary of the killing of jailed African-American activist George Jackson at the hands of a guard in 1971, after he took hostages in a bid to escape San Quentin Prison in California.

It’ll end on the 47-year anniversary of the bloody uprising at Attica Correctional Facility in New York, which left over 40 people dead.