Also available are "mock suppressors/silencers". The killers used pistols fitted with silencers. These engines had improved trucks, larger fuel tanks and modified exhaust silencers. Galli rifles, 100 silencers, 145 rifle telescopes. The use of aftermarket exhaust systems ("cans" or "silencers") is controversial. Since 2020 police can issue permit for firearms with silencers for hunting permits. Minor changes such as&colon; modified lower bodywork, changes to graphics and silver exhaust silencers. The silencers with billet endcaps are also black. Well-characterized regulatory elements include enhancers, silencers, and insulators. There are many classes of regulatory DNA binding sites known as enhancers, insulators and silencers. SR proteins recognize intron and exon enhancers and silencers. The transfer tax for machine guns, silencers, SBR and SBS remained at $200. Enhancers are long-range regulatory elements that increase promoter activity while silencers repress promoter activity. This was achieved by removing the silencers and adding bypass valves. There are also silencers that inhibit transcription.