Are the open cable cars in the Beijing Mutianyu Great Wall safe?

hi! i saw pictures of cable cars in mutianyu and badaling greatwall. the one in mutianyu are the open type cars and the the one in badaling sre the closed type cars.
are the open type cable cars safe? isnt it nerve wrecking ? Im quite afraid of heights. im worried because my tour includes Mutianyu greatwall and I intend to take cable car on my way up and down the wall. Thank you.