N43 height - EPSG:8675

WKT

VERTCS["N43_height", 
	VDATUM["Helsinki_1943"], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", 1.0], 
	UNIT["Meter", 1.0]]

WKT2

VERTCRS["N43_height", 
	VDATUM["Helsinki_1943"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", up, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["EPSG", "8675"]]

Data from @esri/proj-codes

{
  "wkid": 8675,
  "latestWkid": 8675,
  "macro": "PE_VCS_N43_HT",
  "name": "N43_height",
  "wkt": "VERTCS[\"N43_height\",VDATUM[\"Helsinki_1943\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"N43_height\",VDATUM[\"Helsinki_1943\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",up,LENGTHUNIT[\"Meter\",1.0]],ID[\"EPSG\",\"8675\"]]",
  "description": "N43 height",
  "authority": "EPSG",
  "version": "9.4(10.8.0)",
  "deprecated": "no",
  "areaname": "Finland - mainland south of 66~N",
  "extent": {
    "slat": 59.75,
    "nlat": 66.73,
    "llon": 20.95,
    "rlon": 31.59
  }
}