This Is a Treadmill Doctor replacement Treadmill Safety Key. Part Number: 160695. This key fits the following models: Nordictrack: EXP 2000 - NTTL11990, EXP 2000 - NTTL11991, EXP 2000 - NTTL11992, EXP 2000 - NTTL11993, EXP 2000 - NTTL11994, EXP 2000i - NTTL11900, EXP 2000i - NTTL11901, EXP 2000i - NTTL11902, EXP 2000i - NTTL11903, EXP 2000x - NTTL10510, EXP 2000xi - NTTL10610, EXP 2000xi - NTTL10611, EXP 2000xi - NTTL10612, EXP 3000 - NTTL15990, EXP 3000 - NTTL15991, EXP 3000 - NTTL15992, EXP 3000 - NTTL15993, EXP 3000xi - NTTL15900, EXP1000 - 831.298830, EXP1000 - 831.298831, EXP1000 - 831.298832, EXP1000 - 831.298833, EXP1000 - 831.298834, EXP1000 - NCTL09990, EXP1000 - NCTL09992, EXP1000 - NCTL09993, EXP1000 - NETL09901, EXP1000 - NETL09911, EXP1000 - NETL09912, EXP1000 S - 831.298470, EXP1000 X - 831.298770, EXP1000 X - 831.298771, EXP1000 X - 831.298772, EXP1000 X - 831.298773, EXP1000 XI - 831.298670, EXP1000 XI - 831.298671, EXP1000 XI - 831.298672, EXP1000i - 831.298870, EXP1000i - 831.298871, EXP2000 - 831.298840, EXP2000 - 831.298841, EXP2000 - 831.298842, EXP2000 - 831.298843, EXP2000 - 831.298844, EXP2000 - NCTL11990, EXP2000 - NCTL11991, EXP2000 - NCTL11992, EXP2000 - NCTL11994, EXP2000 XI - 831.298680, EXP2000 XI - 831.298681, EXP2000 XI - 831.298682, EXP2000i - 831.298880, EXP2000i - 831.298881, EXP2000i - 831.298882, EXP2000i - 831.298883, EXP3000 - 831.298850, EXP3000 - 831.298851, EXP3000 - 831.298852, EXP3000 - 831.298853, EXP3000 - NCTL15990, EXP3000 - NCTL15991, EXP3000 - NETL15900, EXP3000 - NETL15910, EXP3000 - NETL15911, Summit 3500 R - NTTL15510, Summit 3500 R - NTTL15511, Summit 3500 R - NTTL15512, Summit 3500 R - NTTL15513, Summit 4500 - 831.298890, Summit 4500 - 831.298891, Summit 4500 - 831.298892, Summit 4500 - NTTL16900, Summit 4500 - NTTL16901, Summit 4500 - NTTL16902, Summit 4500 X - 831.298790, Summit 4500 X - 831.298791, Summit 4500 X - NTTL15020, Summit 4500 X - NTTL15021, Summit 5500 - 831.298410, Summit 5500 - NTTL17900.