Note Please: The full set of hotend kits is suitable for Prasu MK4 ONLY, DO NOT fit Prusa MK4 XL, because the thermistors are different. It is a good replacement for Prusa MK4 hotend parts The separated structure is more conducive to replacing nozzle and saving costs. Bi-metal throat tube is made of and titanium, with good heat disspation, rapid heating 500, smooth 0.4um, good thermal insulation. Thermistor for Prusa MK4 Thermistor - 104NT-4-R025H42G (300 max). Suitable for Prusa MK4 ONLY, not suitable for Prusa XL Heating Rod/Heater - 24V 40W Heating block for Prusa MK4 It is made of alnuminum alloy, can meet most printing needs. For Prusa MK4 ONLY Note: Installation guide not included, we strongly recommend you professional installation. Please check as much as possible to make sure the item is what you need. Tips: The product may be updated constantly ,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect Use Colour:As Shown Material:Aluminum Alloy Package Contents: 1 x Aluminum heating block 1 x Thermistor 1 x Heater 1 x Silicone sleeve 1 x Hardened steel nozzle 0.4mm 1 x Bi-metal throat tube Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.