Short answers, pulled from the story.
The SS-20 Saber was a mobile unit capable of carrying three nuclear warheads with a yield of 150 kilotons each. It had a range stretching across Western Europe from deep inside Soviet borders and replaced older systems like the SS-4 Sandal and SS-5 Skean.
Ronald Reagan and Mikhail Gorbachev signed the document at a Washington summit on the 8th of December 1987. The United States Senate approved ratification by a vote of 93 to 5 on the 27th of May 1988, and both nations officially ratified the agreement on the 1st of June 1988.
By the 1st of June 1991, a total of 2,692 missile systems had been destroyed under the treaty terms. The United States dismantled 846 units while the Soviet Union eliminated 1,846 specific weapons including the BGM-109G Ground Launched Cruise Missile and Pershing II.
Russia suspended its own participation following US accusations that it violated the treaty in 2008 by testing the SSC-8 cruise missile with a range exceeding 500 kilometers. Vladimir Putin dismissed these charges as pretexts for American withdrawal after President Donald Trump announced his intention to leave the treaty on the 20th of October 2018.
Inspection activities continued until the 31st of May 2001 as stipulated by the original 13-year agreement. After this date, the United States and Russia shared national technical means of verification and maintained notifications to ensure each state remained compliant.