Original sentence: He has three TNPO-170 periscope vision-blocks to provide vision when his hatch is closed.. The driver's center vision block can be replaced with a TVNO-2 active night binocular vision device for use in night and poor visibility conditions or with a TNPO-350B extended periscope when swimming with the trim vane erected
Edited sentence: He has three TNPO-170 periscope vision-blocks to provide vision when his hatch is closed.The driver's center vision block can be replaced with a TVNO-2 active night binocular vision device for use in night and poor visibility conditions or with a TNPO-350B extended periscope when swimming with the trim vane erected